Search

Phenylketonuria (PKU) is an inherited metabolic disorder that requires lifelong adherence to a low-phenylalanine (Phe) diet to prevent severe neurological complications. However, maintaining dietary adherence can be challenging for patients and their families. This systematic review aimed to comprehensively evaluate the factors affecting adherence to a low-Phe diet in patients with PKU. A systematic search of multiple databases was conducted, and 49 studies were included in the final analysis. The quality of evidence was assessed using the Joanna Briggs Institute levels of evidence and the Quality Assessment with Diverse Studies tool. The review identified four main categories of factors influencing dietary adherence: family-related factors (social, psychological, behavioral, and educational), patient-specific factors (psychological, behavioral, educational, and demographic), environmental factors (healthcare professional support, educational and camp-based interventions, and the COVID-19 pandemic), and therapy-related factors (protein substitute formulation, clinic visits, blood tests, and telemedicine). The findings highlight the complex interplay between elements contributing to dietary adherence in PKU patients and underscore the importance of a multifaceted approach to support patients and their families. Future research should prioritize high-quality longitudinal and experimental studies to provide stronger evidence for the PKU community. [ABSTRACT FROM AUTHOR]

Abstract Background In phenylketonuria (PKU), attending multidisciplinary clinic reviews is an important aspect of life-long care. Since the COVID-19 pandemic, video and telephone clinics are used as alternative methods for people with PKU to have contact with their care team. There is limited research concerning patient preference, experience and perceptions of alternative types of clinic review. Individuals from the UK with PKU and their caregivers were invited to complete an online questionnaire, hosted on the National Society for PKU (NSPKU) website and social media platform. Results Data was available from 203 respondents. Forty one per cent of respondents (n = 49/119) preferred in-person clinics; 41% (n = 49) a hybrid of in-person, video and telephone clinics; 9% (n = 11) video clinics only, 6% (n = 7) telephone only and 3% (n = 3) were unsure. The main respondent obstacles to in-person clinics were costs, travel and time, but this was balanced by the benefits of a physical examination and better patient engagement/motivation. Twenty one per cent (n = 36/169) of respondents were uncomfortable with the number of healthcare professionals (HCPs) in a clinic room. Patients were less likely to consult with a doctor on video (64%, n = 91/143) or phone (50%, n = 59/119) reviews compared to in-person (80%, n = 146/183). Issues with video and telephone reviews included the shorter time length of review, distractions, technical issues and poor patient engagement. Conclusions Online video and telephone clinic platforms were effective in overcoming the challenging circumstances in management, monitoring and treatment of patients with PKU during the COVID-19 pandemic. However, in-person clinics remain the preferred respondent option. It is important that HCPs are flexible, enabling people with PKU a choice of clinic options according to their individual clinical need and circumstances.

Background: In phenylketonuria (PKU), attending multidisciplinary clinic reviews is an important aspect of life-long care. Since the COVID-19 pandemic, video and telephone clinics are used as alternative methods for people with PKU to have contact with their care team. There is limited research concerning patient preference, experience and perceptions of alternative types of clinic review. Individuals from the UK with PKU and their caregivers were invited to complete an online questionnaire, hosted on the National Society for PKU (NSPKU) website and social media platform. Results: Data was available from 203 respondents. Forty one per cent of respondents (n = 49/119) preferred in-person clinics; 41% (n = 49) a hybrid of in-person, video and telephone clinics; 9% (n = 11) video clinics only, 6% (n = 7) telephone only and 3% (n = 3) were unsure. The main respondent obstacles to in-person clinics were costs, travel and time, but this was balanced by the benefits of a physical examination and better patient engagement/motivation. Twenty one per cent (n = 36/169) of respondents were uncomfortable with the number of healthcare professionals (HCPs) in a clinic room. Patients were less likely to consult with a doctor on video (64%, n = 91/143) or phone (50%, n = 59/119) reviews compared to in-person (80%, n = 146/183). Issues with video and telephone reviews included the shorter time length of review, distractions, technical issues and poor patient engagement. Conclusions: Online video and telephone clinic platforms were effective in overcoming the challenging circumstances in management, monitoring and treatment of patients with PKU during the COVID-19 pandemic. However, in-person clinics remain the preferred respondent option. It is important that HCPs are flexible, enabling people with PKU a choice of clinic options according to their individual clinical need and circumstances. [ABSTRACT FROM AUTHOR]

Background: Caregiving experiences in rare diseases (RDs) vary based on factors such as specific clinical entity, disease severity, the child's age, and available support and resources, leading to challenges that significantly impact caregivers' lives. This study investigates whether caregivers of children with different RDs encounter varied aspects of care. Methods: This study was conducted as a self-administered, anonymous, computer-assisted online survey, focusing on the challenges of caregiving for children with RDs. Questions covered aspects such as information availability on RDs, diagnostic processes, modern treatment accessibility, family physicians and specialists, the impact of caregiving on personal life, family dynamics, and financial challenges. To achieve our study objectives, we categorized caregivers of children with RDs into two groups to compare various aspects of caregiving: caregivers of children with phenylketonuria (PKU) (n = 175) and those caring for children with life-limiting rare diseases (LLRD) (n = 226). Results: Caregivers of children with LLRD reported greater emotional challenges, personal sacrifices, and financial burdens compared to caregivers of children with PKU. Significant differences included heightened emotional distress, more frequent conflicts, and lower assessments of healthcare support among LLRD caregivers. Although family support ratings were similar between the groups, perceptions of financial concerns and interactions with the healthcare system varied significantly. Conclusions: This study, representing the inaugural systematic comparison of specific caregiver cohorts overseeing children with RDs across a substantial sample size, provides valuable insights. The findings lay a crucial foundation for precisely tailoring assistance and support initiatives to meet the unique needs of caregivers facing various RDs in diverse contexts. [ABSTRACT FROM AUTHOR]

Infants born to mothers with phenylketonuria (PKU) may develop congenital abnormalities because of elevated phenylalanine (Phe) levels in the mother during pregnancy. Maintenance of blood Phe levels between 120 and 360 μmol/L reduces risks of birth defects. Sapropterin dihydrochloride helps maintain blood Phe control, but there is limited evidence on its risk–benefit ratio when used during pregnancy. Data from the maternal sub‐registries—KAMPER (NCT01016392) and PKUDOS (NCT00778206; PKU‐MOMs sub‐registry)—were collected to assess the long‐term safety and efficacy of sapropterin in pregnant women in a real‐life setting. Pregnancy and infant outcomes, and the safety of sapropterin were assessed. Final data from 79 pregnancies in 57 women with PKU are reported. Sapropterin dose was fairly constant before and during pregnancy, with blood Phe levels maintained in the recommended target range during the majority (82%) of pregnancies. Most pregnancies were carried to term, and the majority of liveborn infants were reported as 'normal' at birth. Few adverse and serious adverse events were considered related to sapropterin, with these occurring in participants with high blood Phe levels. This report represents the largest population of pregnant women with PKU exposed to sapropterin. Results demonstrate that exposure to sapropterin during pregnancy was well‐tolerated and facilitated maintenance of blood Phe levels within the target range, resulting in normal delivery. This critical real‐world data may facilitate physicians and patients to make informed treatment decisions about using sapropterin in pregnant women with PKU and in women of childbearing age with PKU who are responsive to sapropterin. [ABSTRACT FROM AUTHOR]

Background: Those diagnosed with PKU in the early years of newborn screening (NBS) were often discharged from clinic in childhood. Long-term lost to clinic patients may be impacted by untreated PKU and uninformed about current recommendations. We aimed to contact adults away from clinic for 5–50+ years, share current recommendations, offer clinical care, and elicit factors underlying not returning to clinic. Methods: Former patients were identified and offered a virtual meeting with a physician and dietitian for structured interview and education about current guidelines and treatments. Results: We identified 53 eligible patients who had PKU and had not returned to clinic in ≥5 years. Of those 53, 27 were successfully contacted, 16 completed the educational intervention, and 5/16 returned to clinic. Reasons for having been away from clinic included discharge from clinic in childhood and inadequate insurance coverage. Experiences varied and some denied negative impacts after diet discontinuation. Individuals expressed a desire for convenient treatments that aligned with overall health goals. Most participants who completed the educational intervention expressed interest in returning to clinic; however, most did not return within the timeframe of the project. All 27 individuals successfully contacted agreed to be re-contacted with future updates or research opportunities. Discussion: We successfully contacted half of individuals identified as having been lost to clinic follow-up long-term. Limitations included inability to make initial contact, and unwillingness to re-engage by some we reached. Those who agreed to participation desired ongoing PKU clinic and community connection. This experience will inform our process to engage current patients and re-engage those currently lost to care.

The published data on the vitamin status of patients with phenylketonuria (PKU) is contradictory; therefore, this systematic review and meta-analysis evaluated the vitamin status of PKU patients. A comprehensive search of multiple databases (PubMed, Web of Sciences, Cochrane, and Scopus) was finished in March 2024. The included studies compared vitamin levels between individuals diagnosed with early-treated PKU and healthy controls while excluding pregnant and lactating women, untreated PKU or hyperphenylalaninemia cases, control groups receiving vitamin supplementation, PKU patients receiving tetrahydrobiopterin or pegvaliase, and conference abstracts. The risk of bias in the included studies was assessed by the Newcastle–Ottawa scale. The effect sizes were expressed as standardised mean differences. The calculation of effect sizes with 95% CI using fixed-effects models and random-effects models was performed. A p-value < 0.05 was considered statistically significant. The study protocol was registered in the PROSPERO database (CRD42024519589). Out of the initially identified 11,086 articles, 24 met the criteria. The total number of participants comprised 770 individuals with PKU and 2387 healthy controls. The meta-analyses of cross-sectional and case–control studies were conducted for vitamin B12, D, A, E, B6 and folate levels. PKU patients demonstrated significantly higher folate levels (random-effects model, SMD: 1.378, 95% CI: 0.436, 2.320, p = 0.004) and 1,25-dihydroxyvitamin D concentrations (random-effects model, SMD: 2.059, 95% CI: 0.250, 3.868, p = 0.026) compared to the controls. There were no significant differences in vitamin A, E, B6, B12 or 25-dihydroxyvitamin D levels. The main limitations of the evidence include a limited number of studies and their heterogeneity and variability in patients' compliance. Our findings suggest that individuals with PKU under nutritional guidance can achieve a vitamin status comparable to that of healthy subjects. Our study provides valuable insights into the nutritional status of PKU patients, but further research is required to confirm these findings and explore additional factors influencing vitamin status in PKU. [ABSTRACT FROM AUTHOR]

We employed a Sendai virus-based reprogramming method to transform human lymphoblastoid cell lines (LCL) derived from two individuals diagnosed with phenylketonuria (PKU) into induced pluripotent stem cells (iPSC). This reprogramming process involved the expression of the four Yamanaka factors: KLF4, OCT4, SOX2, and C-MYC. The resulting patient-specific iPSCs exhibited a normal karyotype and expressed endogenous pluripotent markers NANOG and OCT-4. Notably, these iPSCs demonstrated strong differentiation capabilities, giving rise to cell populations representing the ectoderm, endoderm, and mesoderm germ layers.

Phenylketonuria is a rare autosomal recessive metabolic disorder mainly due to a significant reduction in the enzyme phenylalanine hydroxylase, resulting in elevation of phenylalanine in the blood. Here, we have established two fibroblast-derived induced pluripotent stem cell lines using Sendai virus-based reprogramming. The established induced pluripotent stem cell lines exhibited a normal karyotype and expressed markers of pluripotency assessed through quantitative PCR, flow cytometry and immunocytochemistry. These cell lines also demonstrated the ability to differentiate into the three primary germ layers of the human body, including ectoderm, endoderm, and mesoderm.

Phenylketonuria (PKU) is an inherited metabolic disorder that requires lifelong adherence to a low-phenylalanine (Phe) diet to prevent severe neurological complications. However, maintaining dietary adherence can be challenging for patients and their families. This systematic review aimed to comprehensively evaluate the factors affecting adherence to a low-Phe diet in patients with PKU. A systematic search of multiple databases was conducted, and 49 studies were included in the final analysis. The quality of evidence was assessed using the Joanna Briggs Institute levels of evidence and the Quality Assessment with Diverse Studies tool. The review identified four main categories of factors influencing dietary adherence: family-related factors (social, psychological, behavioral, and educational), patient-specific factors (psychological, behavioral, educational, and demographic), environmental factors (healthcare professional support, educational and camp-based interventions, and the COVID-19 pandemic), and therapy-related factors (protein substitute formulation, clinic visits, blood tests, and telemedicine). The findings highlight the complex interplay between elements contributing to dietary adherence in PKU patients and underscore the importance of a multifaceted approach to support patients and their families. Future research should prioritize high-quality longitudinal and experimental studies to provide stronger evidence for the PKU community.

One of the most relevant challenges for healthcare providers during the COVID– 19 pandemic has been assuring the continuity of care to patients with complex health needs such as people living with rare diseases (RDs). The COVID–19 pandemic accelerated the healthcare sector's digital transformation agenda. The delivery of telemedicine services instead of many face-to-face procedures has been expanded and, many healthcare services not directly related to COVID-19 treatments shifted online remotely. Many hospitals, specialist centres, patients and families started to use telemedicine because they were forced to. This trend could directly represent a good practice on how care services could be organized and continuity of care could be ensured for patients. If done properly, it could boast improved patient outcomes and become a post COVID-19 major shift in the care paradigm. There is a fragmented stakeholders spectrum, as many questions arise on: how is e-health interacting with 'traditional' healthcare providers; about the role of the European Reference Networks (ERNs); if remote care can retain a human touch and stay patient centric. The manuscript is one of the results of the European Brain Council (EBC) Value of Treatment research project on rare brain disorders focusing on progressive ataxias, dystonia and phenylketonuria with the support of Academic Partners and in collaboration with European Reference Networks (ERNs) experts, applying empirical evidence from different European countries. The main purpose of this work is to investigate the impact of the COVID-19 pandemic on the continuity of care for ataxias, dystonia and phenylketonuria (PKU) in Europe. The analysis carried out makes it possible to highlight the critical points encountered and to learn from the best experiences. Here, we propose a scoping review that investigates this topic, focusing on continuity of care and novel methods (e.g., digital approaches) used to reduce the care disruption. This scoping review was designed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) standards. This work showed that the implementation of telemedicine services was the main measure that healthcare providers (HCPs) put in place and adopted for mitigating the effects of disruption or discontinuity of the healthcare services of people with rare neurological diseases and with neurometabolic disorders in Europe. [ABSTRACT FROM AUTHOR]

Objective: To characterize adherence to Phenylketonuria (PKU) management practices among PKU patients treated at reference sites around Argentina, Brazil, and Mexico. Methods: This is a retrospective, observational, multicenter, and multinational survey-based study using aggregate data. From an initial list of 40 sites, 22 clinicians expressed interest in completing the survey, with 20 clinicians from 20 unique sites fulfilling all the study criteria. The Survey contained 28 questions, including respondent's clinic characteristics, clinic PKU treatment recommendations, and patient adherence to clinic recommendations. Survey was available in local languages, and the respondents were asked to consult their clinic records to complete their responses. Adherence was assessed by target blood phenylalanine (Phe), target blood testing frequency, and clinic visits. Results: A total of 1077 (out of 1377) actively managed PKU patients (seen in the clinic in the last 3 years) from 13 clinics in Brazil, six in Argentina, and one in Mexico were analyzed. Upper blood Phe target was set over 360 μMol/L in 70% of the clinics for adult patients. Around 40% of the patients >30 years old had Phe blood tests done twice a year or less, with 60% of the clinics recommending semestral visits for adults

Abstract Measurement of plasma and dried blood spot (DBS) phenylalanine (Phe) is key to monitoring patients with phenylketonuria (PKU). The relationship between plasma and capillary DBS Phe concentrations has been investigated previously, however, differences in methodology, calibration approach and assumptions about the volume of blood in a DBS sub‐punch has complicated this. Volumetric blood collection devices (VBCDs) provide an opportunity to re‐evaluate this relationship. Paired venous and capillary samples were collected from patients with PKU (n = 51). Capillary blood was collected onto both conventional newborn screening (NBS) cards and VBCDs. Specimens were analysed by liquid‐chromatography tandem mass‐spectrometry (LC–MS/MS) using a common calibrator. Use of VBCDs was evaluated qualitatively by patients. Mean bias between plasma and volumetrically collected capillary DBS Phe was −13%. Mean recovery (SD) of Phe from DBS was 89.4% (4.6). VBCDs confirmed that the volume of blood typically assumed to be present in a 3.2 mm sub‐punch is over‐estimated by 9.7%. Determination of the relationship between plasma and capillary DBS Phe, using a single analytical method, common calibration and VBCDs, demonstrated that once the under‐recovery of Phe from DBS has been taken into account, there is no significant difference in the concentration of Phe in plasma and capillary blood. Conversely, comparison of plasma Phe with capillary DBS Phe collected on a NBS card highlighted the limitations of this approach. Introducing VBCDs for the routine monitoring of patients with PKU would provide a simple, acceptable specimen collection technique that ensures consistent sample quality and produces accurate and precise blood Phe results which are interchangeable with plasma Phe.

Abstract Background Despite early diagnosis and compliance with phenylalanine (Phe)-restricted diets, many individuals with phenylketonuria (PKU) still exhibit neurological changes and experience deficits in working memory and other executive functions. Suboptimal choline intake may contribute to these impairments, but this relationship has not been previously investigated in PKU. The objective of this study was to determine if choline intake is correlated with working memory performance, and if this relationship is modified by diagnosis and metabolic control. Methods This was a cross-sectional study that included 40 adults with PKU and 40 demographically matched healthy adults. Web-based neurocognitive tests were used to assess working memory performance and 3-day dietary records were collected to evaluate nutrient intake. Recent and historical blood Phe concentrations were collected as measures of metabolic control. Results Working memory performance was 0.32 z-scores (95% CI 0.06, 0.58) lower, on average, in participants with PKU compared to participants without PKU, and this difference was not modified by total choline intake (F[1,75] = 0.85, p = 0.36). However, in a subgroup with complete historical blood Phe data, increased total choline intake was related to improved working memory outcomes among participants with well controlled PKU (Phe = 360 µmol/L) after adjusting for intellectual ability and mid-childhood Phe concentrations (average change in working memory per 100 mg change in choline = 0.11; 95% CI 0.02, 0.20; p = 0.02). There also was a trend, albeit nonsignificant (p = 0.10), for this association to be attenuated with increased Phe concentrations. Conclusions Clinical monitoring of choline intake is essential for all individuals with PKU but may have important implications for working memory functioning among patients with good metabolic control. Results from this study should be confirmed in a larger controlled trial in people living with PKU.

Abstract Background The web-based GMDI/SERN PKU Nutrition Management Guideline, published before approval of pegvaliase pharmacotherapy, offers guidance for nutrition management of individuals with phenylketonuria (PKU) treated with dietary therapy and/or sapropterin. An update of this guideline aims to provide recommendations that improve clinical outcomes and promote consistency and best practice in the nutrition management of individuals with PKU receiving pegvaliase therapy. Methodology includes: formulation of a research question; review, critical appraisal, and abstraction of peer-reviewed studies and unpublished practice literature; expert input through Delphi surveys and a Nominal Group process; and external review by metabolic experts. Results Recommendations, summary statements, and strength of evidence are included for each of the following topics: (1) initiating a pegvaliase response trial, (2) monitoring therapy response and nutritional status, (3) managing pegvaliase treatment after response to therapy, (4) education and support for optimal nutrition with pegvaliase therapy, and (5) pegvaliase therapy during pregnancy, lactation, and adolescence. Findings, supported by evidence and consensus, provide guidance for nutrition management of individuals receiving pegvaliase therapy for PKU. Recommendations focus on nutrition management by clinicians, as well as the challenges for individuals with PKU as a result of therapy changes. Conclusions Successful pegvaliase therapy allows the possibility for individuals with PKU to consume an unrestricted diet while still maintaining the benefits of blood phenylalanine control. This necessitates a perspective change in education and support provided to individuals in order to achieve healthy nutrient intake that supports optimal nutritional status. The updated guideline, and companion Toolkit for practical implementation of recommendations, is web-based, allowing for utilization by health care providers, researchers, and collaborators who advocate and care for individuals with PKU. These guidelines are meant to be followed always taking into account the provider’s clinical judgement and considering the individual’s specific circumstances. Open access is available at the Genetic Metabolic Dietitians International ( https://GMDI.org ) and Southeast Regional Genetics Network ( https://managementguidelines.net ) websites.

Adults with PKU require life-long management, and ideally, their care should be in a specialised adult metabolic clinic. Their outcomes and co-morbidities have received much attention, but data are lacking on their experience, satisfaction and expectations about the care they receive. This survey reports the experiences and care adults with PKU receive from specialist metabolic clinics in the UK. The online survey developed by the UK NSPKU (National Society for Phenylketonuria), was placed on the NSPKU website from February 2021 to December 2022, and was completed by adults with PKU (≥18 years) or their carers/family members. Sixty-five adult PKU patients and 9 caregivers of adult patients completed the questionnaire (63% female in total). Only 32% of respondents were following a Phe-restricted diet with protein substitute intake as prescribed; the rest were partially adherent or not on dietary restrictions. Nineteen per cent (n = 14/74) had not been reviewed in clinic for two years. Half of the respondents (50%) described their experience in adult clinics as "good". Half of the patients were unable to contact their dietitians with questions or concerns, and only 24% considered that they received adequate support. Clinic reviews usually included anthropometric (82%) and dietary assessments (64%), discussion on management of PKU in daily life (78%) and a blood test (71%). Eighty-eight per cent reported they had at least one neurocognitive, mental health or behavioural co-morbidity but less than half of the patients reported an assessment on their neurocognitive functioning or mental health issues. Adult male patients appeared to have less detailed clinic review than females. Less than half (44%) of the respondents reported that they performed a blood spot for blood Phe at least monthly, but only 32% considered they had been informed about the risk of high Phe levels in adulthood. Although time, cost and stress related to travelling were barriers to a face-to-face review, more than 40% of patients had concerns about remote appointments. The frequency and extent of monitoring of adults with PKU, attending specialist adult services, were less than those specified by the PKU European guidelines. The care of women of reproductive age is prioritised over men. Adult metabolic health services require further attention, development and resources to provide a high standard and equitable service to patients with PKU. [ABSTRACT FROM AUTHOR]

Background: Phenylketonuria (PKU) is an autosomal recessive disease resulting from a deficiency of the enzyme phenylalanine hydroxylase (PAH). Hyperphenylalaninemias (HPA) due to PAH deficiency are accompanied by a wide variety of clinical, biochemical, and molecular features. To identify and characterize pathogenic variants in the PAH gene and establish a correlation between genotype and biochemical phenotype in patients with PKU from state of Pará in the North Region of Brazil. Methods: All 13 exons of the PAH gene from 32 patients (21 PKU and 11 non‐PKU HPA) were amplified by PCR and submitted to DNA sequencing (Sanger). Biochemical data were obtained from the patients' medical records. Results: Molecular analysis identified 17 pathogenic variants and 3 nonpathogenic variants. The most frequent pathogenic variants were IVS10‐11G>A (7.9%), p. Arg261Gln (7.9%), p. Val388Met (6.3%) and p. Ile65Thr (4.7%). Was observed correlations and inconsistencies between genotype and biochemical phenotype. Conclusion: In PKU patients from state of Pará, North Region of Brazil, a heterogeneous mutation spectrum was revealed, in which the most frequent mutations are variants commonly observed in other Brazilian studies and in the region of the Iberian Peninsula. Molecular analysis performed identified 17 pathogenic mutations. The most frequent pathogenic variants were IVS10‐11G>A (7.9%), p. Arg261Gln (7.9%), p. Val388Met (6.3%) and p. Ile65Thr (4.7%). Was observed correlations and inconsistencies between genotype and phenotype. [ABSTRACT FROM AUTHOR]

Many adults with phenylketonuria (PKU) rely on medical nutrition therapy (MNT; low phenylalanine (Phe) diet with protein substitutes/medical foods) to maintain blood Phe concentrations within recommended ranges and prevent PKU-associated comorbidities. Despite disease detection through newborn screening and introduction of MNT as early as birth, adherence to MNT often deteriorates from childhood onwards, complicating the assessment of its effectiveness in the long term. Via a modified Delphi process, consensus (≥70% agreement) was sought on 19 statements among an international, multidisciplinary 13-member expert panel. After three iterative voting rounds, the panel achieved consensus on 17 statements related to the limitations of the long-term effectiveness of MNT (7), the burden of long-term reliance on MNT (4), and its potential long-term detrimental health effects (6). According to the expert panel, the effectiveness of MNT is limited in the long term, is associated with a high treatment burden, and demonstrates that adults with PKU are often unable to achieve metabolic control through dietary management alone, creating an unmet need in the adult PKU population. [ABSTRACT FROM AUTHOR]

Background and Objectives: Phenylketonuria (PKU) is a genetic disorder of the metabolism of phenylalanine. Patients with PKU have to consume protein‐free or low‐protein products. For the purpose of formulating a low‐protein sponge cake, the effects of Xanthan‐Locust bean hydrocolloids, Pentosan, and egg yolk on the qualitative properties of the product based on corn starch were evaluated. Findings: Independent variables reduced the hardness and improved the cohesiveness of the products. In a distinctive starch‐based batter, the water absorbability of Pentosan and hydrocolloids and the emulsification property of egg yolk reduced the water availability of starch granules. Increasing the gelatinization temperature of granules increased the expansion of air bubbles, reduced the final product's density, and improved the colorimetric properties of the developed product. Conclusions: The best sample had 0.33% hydrocolloids, 1.1% Pentosan, and 1.5% egg yolk. Approximately 80% of the protein content of control was reduced in this sample. Its total protein content (1.27/100 g) and amino acid composition (0.028/100 g phenylalanine and 0.04/100 g tyrosine) were in the acceptable range for PKU. Significance and Novelty: The combination of pentosan and Xanthan‐Locust bean gum at appropriate levels by simulating a gluten‐like network is suitable for the preparation of a low‐protein sponge cake. [ABSTRACT FROM AUTHOR]

Abstract Background Phenylketonuria (PKU) is an autosomal recessive congenital metabolic disorder caused by PAH variants. Previously, approximately 5% of PKU patients remained undiagnosed after Sanger sequencing and multiplex ligation-dependent probe amplification. To date, increasing numbers of pathogenic deep intronic variants have been reported in more than 100 disease-associated genes. Methods In this study, we performed full-length sequencing of PAH to investigate the deep intronic variants in PAH of PKU patients without definite genetic diagnosis. Results We identified five deep intronic variants (c.1199+502A>T, c.1065+241C>A, c.706+368T>C, c.706+531>C, and c.706+608A>C). Of these, the c.1199+502A>T variant was found at high frequency and may be a hotspot PAH variant in Chinese PKU. c.706+531T>C and c.706+608A>C are two novel variants that extend the deep intronic variant spectrum of PAH. Conclusion Deep intronic variant pathogenicity analysis can further improve the genetic diagnosis of PKU patients. In silico prediction and minigene analysis are powerful approaches for studying the functions and effects of deep intronic variants. Targeted sequencing after full-length gene amplification is an economical and effective tool for the detection of deep intron variation in genes with small fragments.

Abstract Background Phenylketonuria (PKU) is a common, congenital, autosomal recessive, metabolic disorder caused by Phenylalanine hydroxylase (PAH) variants. Methods 967 PKU patients from Gansu, China were genotyped by Sanger sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing. We analyzed the variants of PAH exons, their flanking sequences, and introns. Results The detection of deep intronic variants in PAH gene can significantly improve the genetic diagnostic rate of PKU. The distribution of PAH variants among PKU subtypes may be related to the unique genetic background in Gansu, China. Conclusion The identification of PAH hotspot variants will aid the development of large-scale neonatal genetic screening for PKU. The five new PAH variants found in this study further expand the spectrum of PAH variants. Genotype–phenotype correlation analysis may help predict the prognosis of PKU patients and enable precise treatment regimens to be developed.

Abstract Background Phenylketonuria (PKU) is caused by mutations in the phenylalanine hydroxylase (PAH) gene. Our study aimed to predict the phenotype using the allelic genotype. Methods A total of 1291 PKU patients with 623 various variants were used as the training dataset for predicting allelic phenotypes. We designed a common machine learning framework to predict allelic genotypes associated with the phenotype. Results We identified 235 different mutations and 623 various allelic genotypes. The features extracted from the structure of mutations and graph properties of the PKU network to predict the phenotype of PKU were named PPML (PKU phenotype predicted by machine learning). The phenotype of PKU was classified into three different categories: classical PKU (cPKU), mild PKU (mPKU) and mild hyperphenylalaninemia (MHP). Three hub nodes (c.728G>A for cPKU, c.721 for mPKU and c.158G>A for HPA) were used as each classification center, and 5 node attributes were extracted from the network graph for machine learning training features. The area under the ROC curve was AUC = 0.832 for cPKU, AUC = 0.678 for mPKU and AUC = 0.874 for MHP. This suggests that PPML is a powerful method to predict allelic phenotypes in PKU and can be used for genetic counseling of PKU families. Conclusions The web version of PPML predicts PKU allele classification supported by applicable real cases and prediction results. It is an online database that can be used for PKU phenotype prediction http://www.bioinfogenetics.info/PPML/ .

The published data on the vitamin status of patients with phenylketonuria (PKU) is contradictory; therefore, this systematic review and meta-analysis evaluated the vitamin status of PKU patients. A comprehensive search of multiple databases (PubMed, Web of Sciences, Cochrane, and Scopus) was finished in March 2024. The included studies compared vitamin levels between individuals diagnosed with early-treated PKU and healthy controls while excluding pregnant and lactating women, untreated PKU or hyperphenylalaninemia cases, control groups receiving vitamin supplementation, PKU patients receiving tetrahydrobiopterin or pegvaliase, and conference abstracts. The risk of bias in the included studies was assessed by the Newcastle–Ottawa scale. The effect sizes were expressed as standardised mean differences. The calculation of effect sizes with 95% CI using fixed-effects models and random-effects models was performed. A p-value < 0.05 was considered statistically significant. The study protocol was registered in the PROSPERO database (CRD42024519589). Out of the initially identified 11,086 articles, 24 met the criteria. The total number of participants comprised 770 individuals with PKU and 2387 healthy controls. The meta-analyses of cross-sectional and case–control studies were conducted for vitamin B12, D, A, E, B6 and folate levels. PKU patients demonstrated significantly higher folate levels (random-effects model, SMD: 1.378, 95% CI: 0.436, 2.320, p = 0.004) and 1,25-dihydroxyvitamin D concentrations (random-effects model, SMD: 2.059, 95% CI: 0.250, 3.868, p = 0.026) compared to the controls. There were no significant differences in vitamin A, E, B6, B12 or 25-dihydroxyvitamin D levels. The main limitations of the evidence include a limited number of studies and their heterogeneity and variability in patients’ compliance. Our findings suggest that individuals with PKU under nutritional guidance can achieve a vitamin status comparable to that of healthy subjects. Our study provides valuable insights into the nutritional status of PKU patients, but further research is required to confirm these findings and explore additional factors influencing vitamin status in PKU.

Abstract Background Phenylketonuria (PKU) is an autosomal recessive disease resulting from a deficiency of the enzyme phenylalanine hydroxylase (PAH). Hyperphenylalaninemias (HPA) due to PAH deficiency are accompanied by a wide variety of clinical, biochemical, and molecular features. To identify and characterize pathogenic variants in the PAH gene and establish a correlation between genotype and biochemical phenotype in patients with PKU from state of Pará in the North Region of Brazil. Methods All 13 exons of the PAH gene from 32 patients (21 PKU and 11 non‐PKU HPA) were amplified by PCR and submitted to DNA sequencing (Sanger). Biochemical data were obtained from the patients' medical records. Results Molecular analysis identified 17 pathogenic variants and 3 nonpathogenic variants. The most frequent pathogenic variants were IVS10‐11G>A (7.9%), p. Arg261Gln (7.9%), p. Val388Met (6.3%) and p. Ile65Thr (4.7%). Was observed correlations and inconsistencies between genotype and biochemical phenotype. Conclusion In PKU patients from state of Pará, North Region of Brazil, a heterogeneous mutation spectrum was revealed, in which the most frequent mutations are variants commonly observed in other Brazilian studies and in the region of the Iberian Peninsula.

Background: Dietary intervention is to date the mainstay treatment to prevent toxic phenylalanine (Phe) accumulation in PKU patients. Despite success preventing central nervous system damage, there is increasing evidence of possible other unfavorable outcomes affecting other systems, e.g. kidney and bone; underlying mechanisms are yet to be fully elucidated. Methods: This observational, cross-sectional and descriptive study investigated 20 adult with PKU evaluating biochemical parameters, BMD measurements and extrapolating data from 3-days food records and protein substitutes (PS) and special low protein foods (SLPF) composition. Results: Blood gas venous analysis (VBG) indices were indicative of metabolic acidosis in 60% of PKU patients and VBG pH significantly correlated with BMD's Z-score (p-value = 0.022) even if its overall mean was in range (−1.29). Low bone mineral density for chronological age (Z-score

Introduction: Clinical management of rare diseases often fails to acknowledge the challenges faced by caregivers. Whilst management of phenylketonuria (PKU) may not be considered as dire as other conditions, most studies primarily concentrate on clinical issues, dietary adherence, or the quality of life of the PKU patients, leaving caregivers in the background. The aim of the study was to evaluate the psychosocial effects of PKU on family caregivers. Methods: Between October 30th, 2022 and February 28th, 2023, we collected data from caregivers of children with PKU using an anonymous, self-administered, computer-assisted online questionnaire. The survey was distributed among to patients during their regular visits to five Polish PKU treatment centers. Results: A total of 159 Polish caregivers of children with PKU completed the survey. This research shows that while women caregivers were more likely to be unemployed due to their responsibilities for childcare (50.3% compared to 0% for men), and men caregivers were more likely to be employed full-time (93.8% compared to 40.6% for women), the former reported higher emotional engagement in caregiving (88.1% vs 56.3% respectively). Significantly, unemployed mothers reported higher levels of loneliness, helplessness, and emotional control problems, and lacked psychological/emotional support more often than employed mothers. This research also shows a statistically significant positive correlation between mothers' education level and financial situation (p

(1) Background: Poor palatability, large volume, and lack of variety of some liquid and powdered protein substitutes (PSs) for patients with phenylketonuria (PKU) and tyrosinemia (TYR) can result in poor adherence. This study aimed to evaluate a new unflavoured, powdered GMP-based PS designed to be mixed into drinks, foods, or with other PSs, in patients with PKU and TYR. (2) Methods: Paediatric and adult community-based patients were recruited from eight metabolic centres and prescribed ≥1 sachet/day (10 g protein equivalent (PE)) of the Mix-In-style PS over 28 days. Adherence, palatability, GI tolerance, and metabolic control were recorded at baseline and follow-up. Patients who completed at least 7 days of intervention were included in the final analysis. (3) Results: Eighteen patients (3–45 years, nine males) with PKU (n = 12) and TYR (n = 6) used the Mix-In-style PS for ≥7 days (mean 26.4 days (SD 4.6), range 11–28 days) alongside their previous PS, with a mean intake of 16.7 g (SD 7.7) PE/day. Adherence was 86% (SD 25), and GI tolerance was stable, with n = 14 experiencing no/no new symptoms and n = 3 showing improved symptoms compared to baseline. Overall palatability was rated satisfactory by 78% of patients, who successfully used the Mix-In-style PS in various foods and drinks, including smoothies, squash, and milk alternatives, as a top-up to meet their protein needs. There was no concern regarding safety/metabolic control during the intervention. (4) Conclusions: The 'Mix-In'-style PS was well adhered to, accepted, and tolerated. Collectively, these data show that providing a flexible, convenient, and novel format of PS can help with adherence and meet patients' protein needs. [ABSTRACT FROM AUTHOR]

(1) Background: Good adherence to a Phe-restricted diet supplemented with an adequate amount of a protein substitute (PS) is important for good clinical outcomes in PKU. Glycomacropeptide (cGMP)-PSs are innovative, palatable alternatives to amino acid-based PSs (AA-PS). This study aimed to evaluate a new cGMP-PS in liquid and powder formats in PKU. (2) Methods: Children and adults with PKU recruited from eight centres were prescribed at least one serving/day of cGMP-PS for 7–28 days. Adherence, acceptability, and gastrointestinal tolerance were recorded at baseline and the end of the intervention. The blood Phe levels reported as part of routine care during the intervention were recorded. (3) Results: In total, 23 patients (powder group, n = 13; liquid group, n = 10) completed the study. The majority assessed the products to be palatable (77% of powder group; 100% of liquid group) and well tolerated; the adherence to the product prescription was good. A total of 14 patients provided blood Phe results during the intervention, which were within the target therapeutic range for most patients (n = 11) at baseline and during the intervention. (4) Conclusions: These new cGMP-PSs were well accepted and tolerated, and their use did not adversely affect blood Phe control. [ABSTRACT FROM AUTHOR]

In phenylketonuria (PKU), natural protein tolerance is defined as the maximum natural protein intake maintaining a blood phenylalanine (Phe) concentration within a target therapeutic range. Tolerance is affected by several factors, and it may differ throughout a person's lifespan. Data on lifelong Phe/natural protein tolerance are limited and mostly reported in studies with low subject numbers. This systematic review aimed to investigate how Phe/natural protein tolerance changes from birth to adulthood in well-controlled patients with PKU on a Phe-restricted diet. Five electronic databases were searched for articles published until July 2020. From a total of 1334 results, 37 articles met the eligibility criteria (n = 2464 patients), and 18 were included in the meta-analysis. The mean Phe (mg/day) and natural protein (g/day) intake gradually increased from birth until 6 y (at the age of 6 months, the mean Phe intake was 267 mg/day, and natural protein intake was 5.4 g/day; at the age of 5 y, the mean Phe intake was 377 mg/day, and the natural protein intake was 8.9 g/day). However, an increase in Phe/natural protein tolerance was more apparent at the beginning of late childhood and was >1.5-fold that of the Phe tolerance in early childhood. During the pubertal growth spurt, the mean natural protein/Phe tolerance was approximately three times higher than in the first year of life, reaching a mean Phe intake of 709 mg/day and a mean natural protein intake of 18 g/day. Post adolescence, a pooled analysis could only be performed for natural protein intake. The mean natural protein tolerance reached its highest (32.4 g/day) point at the age of 17 y and remained consistent (31.6 g/day) in adulthood, but limited data were available. The results of the meta-analysis showed that Phe/natural protein tolerance (expressed as mg or g per day) increases with age, particularly at the beginning of puberty, and reaches its highest level at the end of adolescence. This needs to be interpreted with caution as limited data were available in adult patients. There was also a high degree of heterogeneity between studies due to differences in sample size, the severity of PKU, and target therapeutic levels for blood Phe control. [ABSTRACT FROM AUTHOR]

Objective: Phenylketonuria (PKU) is a rare inherited metabolic disorder characterised by elevated phenylalanine (Phe) concentrations that can exert neurotoxic effects if untreated or upon treatment discontinuation. This systematic review supported by expert opinion aims to raise awareness among the neurological community on neurological complications experienced by adults with PKU (AwPKU). Methods: The PubMed database was searched for articles on neurological signs and symptoms in AwPKU published before March 2022. In addition, two virtual advisory boards were held with a panel of seven neurologists and two metabolic physicians from Germany and Austria. Findings are supported by three illustrative patient cases. Results: Thirty-nine articles were included. Despite early diagnosis and treatment, neurological signs and symptoms (e.g. ataxia, brisk tendon reflexes, tremor, visual impairment) can emerge in adulthood, especially if treatment has been discontinued after childhood. In PKU, late-onset neurological deficits often co-occur with cognitive impairment and psychiatric symptoms, all of which can be completely or partially reversed through resumption of treatment. Conclusion: Ideally, neurologists should be part of the PKU multidisciplinary team, either to bring lost to follow-up patients back to clinic or to manage symptoms in referred patients, considering that symptoms are often reversible upon regaining metabolic control. The current findings have been combined in a leaflet that will be disseminated among neurologists in Germany and Austria to create awareness. [ABSTRACT FROM AUTHOR]

Phenylketonuria (PKU) is an inherited disorder of protein metabolism. It is generally treated using dietary management with limited intake of phenylalanine (Phe). Partial breastfeeding (BF) is encouraged among mothers of infants with PKU, together with a Phe-free mixture of synthetic amino acids. Our aim was to describe our current BF rates and complementary feeding practices, as well as examining parental experiences of infant feeding. The objective was to better understand the challenges faced by families so that improvements can be made to clinical care. A chart review was carried out on 39 PKU patients, examining the BF rate and duration, use of second stage synthetic protein (SP), and average complementary feeding age. A parental questionnaire on complementary feeding and BF experience was designed: 26% of babies were partially breastfed at three months of age; 70% of mums would like to have breastfed for longer and cited PKU as a reason for stopping; 52% of parents reported challenges during the complementary feeding process including food refusal, protein calculation, and anxiety around maintaining good Phe levels. Suggestions to improve BF continuation and duration include active promotion of the benefits and suitability, access to lactation consultant, and peer support. The delay in introducing a second stage SP may contribute to long-term bottle use for SP. Improved patient education, written resources, and support is necessary to improve food choices and long-term acceptance of SP. [ABSTRACT FROM AUTHOR]

Copyright of Social Sciences Studies is the property of Social Sciences Studies and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Parents of a child with phenylketonuria (PKU) face many challenges in childcare. It is crucial for health care workers to understand the situation of parents of a child with PKU and their needs. The purpose of this study was to explore the life story of parents with a child with PKU. This qualitative study has been done with a conventional content analysis approach. Twenty-four parents were selected purposefully. A semi-structured interview was conducted. Data analysis identified three main themes, which included parental reactions, consequences of a child with PKU in parents, and parents' needs. Parents of children with PKU can be considered people at risk for mental health because of their feelings of isolation and their lonely struggle to manage the disease and its effects on their child. This study shows that mothers need more support due to the misconceptions in and attitudes of their social environment. Therefore, it is necessary to understand this group, their needs and lives, and provide further support and promote empathy in the health system for the parents. [ABSTRACT FROM AUTHOR]

Background: Despite early diagnosis and compliance with phenylalanine (Phe)-restricted diets, many individuals with phenylketonuria (PKU) still exhibit neurological changes and experience deficits in working memory and other executive functions. Suboptimal choline intake may contribute to these impairments, but this relationship has not been previously investigated in PKU. The objective of this study was to determine if choline intake is correlated with working memory performance, and if this relationship is modified by diagnosis and metabolic control. Methods: This was a cross-sectional study that included 40 adults with PKU and 40 demographically matched healthy adults. Web-based neurocognitive tests were used to assess working memory performance and 3-day dietary records were collected to evaluate nutrient intake. Recent and historical blood Phe concentrations were collected as measures of metabolic control. Results: Working memory performance was 0.32 z-scores (95% CI 0.06, 0.58) lower, on average, in participants with PKU compared to participants without PKU, and this difference was not modified by total choline intake (F[1,75] = 0.85, p = 0.36). However, in a subgroup with complete historical blood Phe data, increased total choline intake was related to improved working memory outcomes among participants with well controlled PKU (Phe = 360 µmol/L) after adjusting for intellectual ability and mid-childhood Phe concentrations (average change in working memory per 100 mg change in choline = 0.11; 95% CI 0.02, 0.20; p = 0.02). There also was a trend, albeit nonsignificant (p = 0.10), for this association to be attenuated with increased Phe concentrations. Conclusions: Clinical monitoring of choline intake is essential for all individuals with PKU but may have important implications for working memory functioning among patients with good metabolic control. Results from this study should be confirmed in a larger controlled trial in people living with PKU. [ABSTRACT FROM AUTHOR]

Phenylketonuria (PKU) is an inherited error of metabolism. Its prevalence is estimated at 1/50.000 but ranges from 1/2600 in Turkey, 1/50.000 in the UK and 1/100.000 in Japan. In 98% of the cases, it is caused by the autosomal recessive transmission of a mutation of the PAH gene (12q23.2) which codes for phenylalanine hydroxylase (PAH), the enzyme that converts phenylalanine to tyrosine. In all other cases, it is caused by the autosomal recessive transmission of a mutation of one of the genes responsible for the synthesis or regeneration of tetrahydrobiopterin (BH4).These are: the GCH1 gene coding for GTP cyclohydroxylase1 (14q22.2), the PTS gene coding for 6-pyruvoyl-tetrahydropterine synthase (11q23.1), the PCBD gene coding for pterin-4α-carbinolamine dehydratase (10q22.2) or the QDPR gene coding for dihydropterin reductase (4p15.32). Most of these cases are caused by a dihydropterin reductase deficiency. They are called BH4 deficiency or defects in pterin metabolism. BH4 is a cosubstrate of phenylalanine hydroxylase (see figure at the end of the text) but it is also involved in the synthesis of the amino acids tyrosine, tryptophan and arginine. A deficiency in the production of these amino acids results in a deficiency of the neurotransmitters dopamine, serotonin and nitric oxide. In addition, in rare cases, hyperphenylalaninaemia may be caused by a mutation in DNAJC12, a protein responsible for the proper folding of PHA (4). [ABSTRACT FROM AUTHOR]

Background: The web-based GMDI/SERN PKU Nutrition Management Guideline, published before approval of pegvaliase pharmacotherapy, offers guidance for nutrition management of individuals with phenylketonuria (PKU) treated with dietary therapy and/or sapropterin. An update of this guideline aims to provide recommendations that improve clinical outcomes and promote consistency and best practice in the nutrition management of individuals with PKU receiving pegvaliase therapy. Methodology includes: formulation of a research question; review, critical appraisal, and abstraction of peer-reviewed studies and unpublished practice literature; expert input through Delphi surveys and a Nominal Group process; and external review by metabolic experts. Results: Recommendations, summary statements, and strength of evidence are included for each of the following topics: (1) initiating a pegvaliase response trial, (2) monitoring therapy response and nutritional status, (3) managing pegvaliase treatment after response to therapy, (4) education and support for optimal nutrition with pegvaliase therapy, and (5) pegvaliase therapy during pregnancy, lactation, and adolescence. Findings, supported by evidence and consensus, provide guidance for nutrition management of individuals receiving pegvaliase therapy for PKU. Recommendations focus on nutrition management by clinicians, as well as the challenges for individuals with PKU as a result of therapy changes. Conclusions: Successful pegvaliase therapy allows the possibility for individuals with PKU to consume an unrestricted diet while still maintaining the benefits of blood phenylalanine control. This necessitates a perspective change in education and support provided to individuals in order to achieve healthy nutrient intake that supports optimal nutritional status. The updated guideline, and companion Toolkit for practical implementation of recommendations, is web-based, allowing for utilization by health care providers, researchers, and collaborators who advocate and care for individuals with PKU. These guidelines are meant to be followed always taking into account the provider's clinical judgement and considering the individual's specific circumstances. Open access is available at the Genetic Metabolic Dietitians International (https://GMDI.org) and Southeast Regional Genetics Network (https://managementguidelines.net) websites. [ABSTRACT FROM AUTHOR]

Background: Phenylketonuria (PKU) is an autosomal recessive congenital metabolic disorder caused by PAH variants. Previously, approximately 5% of PKU patients remained undiagnosed after Sanger sequencing and multiplex ligation-dependent probe amplification. To date, increasing numbers of pathogenic deep intronic variants have been reported in more than 100 disease-associated genes. Methods: In this study, we performed full-length sequencing of PAH to investigate the deep intronic variants in PAH of PKU patients without definite genetic diagnosis. Results: We identified five deep intronic variants (c.1199+502A>T, c.1065+241C>A, c.706+368T>C, c.706+531>C, and c.706+608A>C). Of these, the c.1199+502A>T variant was found at high frequency and may be a hotspot PAH variant in Chinese PKU. c.706+531T>C and c.706+608A>C are two novel variants that extend the deep intronic variant spectrum of PAH. Conclusion: Deep intronic variant pathogenicity analysis can further improve the genetic diagnosis of PKU patients. In silico prediction and minigene analysis are powerful approaches for studying the functions and effects of deep intronic variants. Targeted sequencing after full-length gene amplification is an economical and effective tool for the detection of deep intron variation in genes with small fragments. [ABSTRACT FROM AUTHOR]

Background: A diagnosis of phenylketonuria (PKU) in an infant is a devastating and overwhelming event for their parents. Providing appropriate information and support is paramount, especially at the beginning of a child's life. Investigating if parents are receiving the right support is important for continued care. Methodology: An online survey was distributed to explore parents' perceptions of current support and information provided by their healthcare provider and to rate sources of other support (n = 169 participants). Results: Dietitians received the highest (85%) rate of "very helpful" support. Overall, parents found Facebook to be helpful for support but had mixed reactions when asked if healthcare professionals (HCPs) should provide advice as part of the groups. When rating the most effective learning methods, the top three were 1:1 teaching sessions (n = 109, 70%), picture books (n = 73, 50%), and written handouts (n = 70, 46%). Conclusion: Most parents are happy with the support and information they receive from their dietitian but required more support from other HCPs. Facebook groups provide parents with the social support that HCPs and their family may be unable to offer, suggesting a place for social media in future PKU care. [ABSTRACT FROM AUTHOR]

Background: Phenylketonuria (PKU) is a common, congenital, autosomal recessive, metabolic disorder caused by Phenylalanine hydroxylase (PAH) variants. Methods: 967 PKU patients from Gansu, China were genotyped by Sanger sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing. We analyzed the variants of PAH exons, their flanking sequences, and introns. Results: The detection of deep intronic variants in PAH gene can significantly improve the genetic diagnostic rate of PKU. The distribution of PAH variants among PKU subtypes may be related to the unique genetic background in Gansu, China. Conclusion: The identification of PAH hotspot variants will aid the development of large-scale neonatal genetic screening for PKU. The five new PAH variants found in this study further expand the spectrum of PAH variants. Genotype–phenotype correlation analysis may help predict the prognosis of PKU patients and enable precise treatment regimens to be developed. [ABSTRACT FROM AUTHOR]

Background: Phenylketonuria (PKU) is caused by mutations in the phenylalanine hydroxylase (PAH) gene. Our study aimed to predict the phenotype using the allelic genotype. Methods: A total of 1291 PKU patients with 623 various variants were used as the training dataset for predicting allelic phenotypes. We designed a common machine learning framework to predict allelic genotypes associated with the phenotype. Results: We identified 235 different mutations and 623 various allelic genotypes. The features extracted from the structure of mutations and graph properties of the PKU network to predict the phenotype of PKU were named PPML (PKU phenotype predicted by machine learning). The phenotype of PKU was classified into three different categories: classical PKU (cPKU), mild PKU (mPKU) and mild hyperphenylalaninemia (MHP). Three hub nodes (c.728G>A for cPKU, c.721 for mPKU and c.158G>A for HPA) were used as each classification center, and 5 node attributes were extracted from the network graph for machine learning training features. The area under the ROC curve was AUC = 0.832 for cPKU, AUC = 0.678 for mPKU and AUC = 0.874 for MHP. This suggests that PPML is a powerful method to predict allelic phenotypes in PKU and can be used for genetic counseling of PKU families. Conclusions: The web version of PPML predicts PKU allele classification supported by applicable real cases and prediction results. It is an online database that can be used for PKU phenotype prediction http://www.bioinfogenetics.info/PPML/. [ABSTRACT FROM AUTHOR]

Background: Hyperphenylalaninemias (HPA) are due to several gene mutations, of which the PAH gene is the most frequently involved. Prevalence and incidence of disease vary between populations, with genotype/phenotype correlations not always capable to correctly predict disease severity. The aim of this study was to give an overview of PAH mutations among one of the largest cohort of patients among Europe, born in Lombardy (Italy) starting from late 1970 s and including over a 60 years of activity; furthermore, to evaluate and discuss identified genotype/phenotype correlations and related reliability. Patients/Methods: Eight hundred and twenty‐six HPA patients in current follow‐up at the San Paolo Hospital in Milan (Italy) were retrospectively reviewed, including molecular results and allelic phenotype and genotype values (attributed on the basis of the APV/GPV system) to verify genotype–phenotype correlations. Results: A total of 166 different PAH variants were reviewed; of those, seven variants were identified as not previously described in literature. Most frequently reported variant was p.Ala403Val, followed by p.Arg261Gln, p.Val245Ala, IVS10‐11 g>a, p.Tyr414Cys and p.Leu48Ser. Phenotype prediction, based on APV/GPV, matched the actual phenotype in most cases, but not always. Conclusion/Discussion: The cohort of patients included in this study constitute a representative sample of the HPA population worldwide. Studies on this sample may allow to improve clinical and genetic evaluation performances for affected patients, consequently to develop personalized medicine interventions and provide more precise indications on the correct treatment approach based on the accumulated evidence, also in light of a prognostically reliable but not always conclusive APV/GPV system. [ABSTRACT FROM AUTHOR]

Introduction. Phenylketonuria (PKU), a genetic disease with autosomal dominant transmission, is the most frequent inborn error in aminoacid metabolism. The variations in phenylalanine-hydroxylase (PAH) gene lead to a lowered enzymatic activity causing hyperphenylalaninemia. PKU has a mean European prevalence of 1:10,000 newborns, with a large variation in different ethnicities and geographic regions. The large genetic variability (over 1200 genetic variants known) as well as other factors determines a wide spectrum of metabolic phenotypes. Untreated, PKU leads to irreversible intellectual disability, low stature, hypopigmentation, motor deficits, seizures, but the early diagnosis and treatment enables almost normal somatic and mental development. Aim. The aim of this study is the determination of the impact of non-genetic factors over the clinical phenotype of PKU patients in a region of north-west Romania. Material and method. The study group is formed from 44 patients diagnosed with phenylketonuria in the 1981 – 2021 period, found in the database of Bihor Regional Center for Medical Genetics, Emergency Clinical County Hospital, Oradea, Romania. The collected data was referring to the age, sex and domicile of the patients, the age of the diagnosis and the beginning of the treatment, also the metabolic control over the years, the metabolic phenotype of the patients and its impact on the clinical phenotype (IQ, the presence or absence of intellectual disability or the existence of a specific clinical phenotype). Results. The majority of patients (66%) were diagnosticated with phenylketonuria in the first 4 months of life, although there were cases with a late diagnosis, 20.5% of the patients were diagnosticated after the age of 1 year. Based on the pre-treatment plasmatic levels of phenylalanine, the majority of cases (72.7%) had a severe metabolic phenotype (classic PKU - cPKU), 20.5% of cases had a milder form of PKU (mPKU) and 6.8% of patients were found with a mild hyperphenylalaninemia (HPA). In the case of 23 patients, an optimal metabolic control was not obtained. The specific phenotype (blonde hair, light skin, blue eyes) was found in 22.7% of cases, 77.3% not having these features. At 68.2% of cases intellectual disability was found, with different levels of severity: 5 patients (11.5%) had liminal intellect, 9 patients (20.5%) had mild mental retardation, 6 patients (13.6%) had moderate mental retardation, 9 cases (20.5%) were with severe mental retardation and 1 patient (2.3%) had profound mental retardation; 31.8% of cases had normal intellect. The prevalence in Bihor county is 1:7,843 newborns. Discussions. A partial or, in rare cases, total lack of dietetic treatment was observed in all patients over 20 years old (current age). The delay in treatment initiation or an insufficient treatment, with a suboptimal metabolic control, will affect patient’s intellect, regardless of metabolic phenotype. If in 20 years old patients, or older, the main reason for mental retardation is the lack of dietetic treatment availability in the first years of life, for the younger patients the reason for mental retardation is usually a lack of compliance with the treatment. The majority of metabolic phenotypes is cPKU, in concordance with the literature data; the mild phenotype (HPA) was observed in a small percentage of patients, smaller than the data reported in the literature. In the first two studied decades the mild phenotypes were seldom observed. In the absence of screening tests or suggestive clinical manifestation it can be assumed that HPA patients remained undiagnosed, which would explain the small HPA percentage in the study group. A significant improvement in metabolic control in younger patients compared with older ones was observed, which denotes a better access to specific alimentation on one side, and o the other side, a better understanding of the disease from the patients and their families. Also, this study confirms a known fact that the diet in PKU is of great importance in the disease evolution. In this study there were included patients with severe metabolic phenotype with good metabolic control which reached adulthood without intellectual deficits, with higher education, social integrated and also patients with mild metabolic phenotype but with a poor metabolic control which developed intellectual deficiency. Conclusions. The PKU prevalence in Bihor county is higher than the estimated national value. The late diagnosis and treatment or the poor metabolic control led to intellectual disability, regardless of the metabolic phenotype. PKU screening and the better access to treatment allows younger generations of patients to enjoy a superior quality of life than the patients from the first two studied decades.

Phenylketonuria (PKU) is an inborn error caused by deficiencies in phenylalanine (Phe) metabolism. Mutations in the phenylalanine hydroxylase (PAH) gene are the main cause of the disease whose signature hallmarks of toxically elevated levels of Phe accumulation in plasma and organs such as the brain, result in irreversible intellectual disability. Here, we present a unique approach to treating PKU deficiency by using an mRNA replacement therapy. A full-length mRNA encoding human PAH (hPAH) is encapsulated in our proprietary lipid nanoparticle LUNAR and delivered to a Pahenu2 mouse model that carries a missense mutation in the mouse PAH gene. Animals carrying this missense mutation develop hyperphenylalanemia and hypotyrosinemia in plasma, two clinical features commonly observed in the clinical presentation of PKU. We show that intravenous infusion of LUNAR-hPAH mRNA can generate high levels of hPAH protein in hepatocytes and restore the Phe metabolism in the Pahenu2 mouse model. Together, these data establish a proof of principle of a novel mRNA replacement therapy to treat PKU.

Abstract Background Hyperphenylalaninemias (HPA) are due to several gene mutations, of which the PAH gene is the most frequently involved. Prevalence and incidence of disease vary between populations, with genotype/phenotype correlations not always capable to correctly predict disease severity. The aim of this study was to give an overview of PAH mutations among one of the largest cohort of patients among Europe, born in Lombardy (Italy) starting from late 1970 s and including over a 60 years of activity; furthermore, to evaluate and discuss identified genotype/phenotype correlations and related reliability. Patients/Methods Eight hundred and twenty‐six HPA patients in current follow‐up at the San Paolo Hospital in Milan (Italy) were retrospectively reviewed, including molecular results and allelic phenotype and genotype values (attributed on the basis of the APV/GPV system) to verify genotype–phenotype correlations. Results A total of 166 different PAH variants were reviewed; of those, seven variants were identified as not previously described in literature. Most frequently reported variant was p.Ala403Val, followed by p.Arg261Gln, p.Val245Ala, IVS10‐11 g>a, p.Tyr414Cys and p.Leu48Ser. Phenotype prediction, based on APV/GPV, matched the actual phenotype in most cases, but not always. Conclusion/Discussion The cohort of patients included in this study constitute a representative sample of the HPA population worldwide. Studies on this sample may allow to improve clinical and genetic evaluation performances for affected patients, consequently to develop personalized medicine interventions and provide more precise indications on the correct treatment approach based on the accumulated evidence, also in light of a prognostically reliable but not always conclusive APV/GPV system.

• This White Paper offers a neurocognitive assessment platform for clinical trials in PKU. • It describes 5 neuropsychological domains relevant to outcomes in PKU. • Criteria for measures to be included in the Assessment Platform are defined. • Both Performance and Patient Reported Outcome measures are recommended. • Once implemented, this Platform may accelerate approval of new PKU treatments. [ABSTRACT FROM AUTHOR]

Adults with PKU require life-long management, and ideally, their care should be in a specialised adult metabolic clinic. Their outcomes and co-morbidities have received much attention, but data are lacking on their experience, satisfaction and expectations about the care they receive. This survey reports the experiences and care adults with PKU receive from specialist metabolic clinics in the UK. The online survey developed by the UK NSPKU (National Society for Phenylketonuria), was placed on the NSPKU website from February 2021 to December 2022, and was completed by adults with PKU (≥18 years) or their carers/family members. Sixty-five adult PKU patients and 9 caregivers of adult patients completed the questionnaire (63% female in total). Only 32% of respondents were following a Phe-restricted diet with protein substitute intake as prescribed; the rest were partially adherent or not on dietary restrictions. Nineteen per cent (n = 14/74) had not been reviewed in clinic for two years. Half of the respondents (50%) described their experience in adult clinics as “good”. Half of the patients were unable to contact their dietitians with questions or concerns, and only 24% considered that they received adequate support. Clinic reviews usually included anthropometric (82%) and dietary assessments (64%), discussion on management of PKU in daily life (78%) and a blood test (71%). Eighty-eight per cent reported they had at least one neurocognitive, mental health or behavioural co-morbidity but less than half of the patients reported an assessment on their neurocognitive functioning or mental health issues. Adult male patients appeared to have less detailed clinic review than females. Less than half (44%) of the respondents reported that they performed a blood spot for blood Phe at least monthly, but only 32% considered they had been informed about the risk of high Phe levels in adulthood. Although time, cost and stress related to travelling were barriers to a face-to-face review, more than 40% of patients had concerns about remote appointments. The frequency and extent of monitoring of adults with PKU, attending specialist adult services, were less than those specified by the PKU European guidelines. The care of women of reproductive age is prioritised over men. Adult metabolic health services require further attention, development and resources to provide a high standard and equitable service to patients with PKU.

Many adults with phenylketonuria (PKU) rely on medical nutrition therapy (MNT; low phenylalanine (Phe) diet with protein substitutes/medical foods) to maintain blood Phe concentrations within recommended ranges and prevent PKU-associated comorbidities. Despite disease detection through newborn screening and introduction of MNT as early as birth, adherence to MNT often deteriorates from childhood onwards, complicating the assessment of its effectiveness in the long term. Via a modified Delphi process, consensus (≥70% agreement) was sought on 19 statements among an international, multidisciplinary 13-member expert panel. After three iterative voting rounds, the panel achieved consensus on 17 statements related to the limitations of the long-term effectiveness of MNT (7), the burden of long-term reliance on MNT (4), and its potential long-term detrimental health effects (6). According to the expert panel, the effectiveness of MNT is limited in the long term, is associated with a high treatment burden, and demonstrates that adults with PKU are often unable to achieve metabolic control through dietary management alone, creating an unmet need in the adult PKU population.

Laurie Bernstein,1,2 Joyanna Hansen,3 Christian Kogelmann,4 Margret Ellerbrok,4 Maria Gizewska,5 Sommer Gaughan,6 Julio Cesar Rocha,7– 9 Amaya Belanger,10 Fran Rohr2 1Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Aurora, CO, USA; 2Met Ed Co, Boulder, CO, USA; 3Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA; 4University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 5Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Cardiology of the Developmental Age, Pomeranian Medical University, Szczecin, Poland; 6Inherited Metabolic Diseases Clinic, Children’s Hospital Colorado, Aurora, CO, USA; 7Nutrition and Metabolism, NOVA Medical School | Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisboa, 1169-056, Portugal; 8CINTESIS - Center for Health Technology and Services Research, Porto, Portugal; 9Reference Centre of Inherited Metabolic Diseases, Centro Hospitalar Universitário de Lisboa Central, Lisboa, 1169-045, Portugal; 10Hospital Universitario Ramon y Cajal, Madrid, SpainCorrespondence: Fran Rohr Email fran.rohr@met-ed.netAbstract: Phenylketonuria (PKU) is one of the most common inherited metabolic disorders, and historically has required affected individuals to follow a severely protein-restricted diet with medical food for life. A novel enzyme substitution therapy, pegvaliase, allows many adults with PKU on therapy to have a reduction in blood phenylalanine (Phe) while on an unrestricted diet. However, there is limited information on optimal nutrition management of individuals with PKU on pegvaliase therapy. This manuscript summarizes a virtual European meeting focused on nutrition management of individuals on pegvaliase therapy, including three case studies and a patient perspective that together provide clinical insights into the real-world management of individuals with PKU on pegvaliase.Keywords: PKU, phenylketonuria, pegvaliase, medical nutrition therapy

Pegvaliase, an injectable form of phenylalanine ammonia lyase, is an enzyme substitution therapy for adults with phenylketonuria (PKU). Experience with pegvaliase during lactation is scarce. Limited evidence suggests that pegvaliase does not pass into breast milk. The case presented here describes the pregnancy and lactation experience of a woman with PKU who was treated with pegvaliase prior to pregnancy, discontinued pegvaliase and was treated with a phenylalanine-restricted diet in preparation for and during pregnancy, and then reinstituted pegvaliase two weeks after giving birth and throughout lactation. No pegvaliase activity was detected in pumped breast milk samples prior to reinstituting pegvaliase, and at doses of 80, 110 and 140 mg/week during lactation. The phenylalanine content of breast milk samples collected during pegvaliase therapy were not significantly different than controls, and the infant has grown and developed normally, indicating that pegvaliase therapy during lactation is safe.

Phenylketonuria (PKU) is a rare genetic disease that causes brain toxicity due to the inability of the body to convert dietary phenylalanine to tyrosine by the action of phenylalanine hydroxylase. The only treatment for PKU so far is lifelong dietary intervention to ensure normal human growth and neurodevelopment. However, in adults, low long-term adherence to this type of dietary intervention has been observed. Given the important role of the intestinal microbiota in the process of digestion and disease prevention, probiotics could be a therapeutic strategy to help degrade dietary phenylalanine, reducing its levels before ingestion. Genetically modified probiotics designed as live biotherapeutic agents for the treatment of specific diseases are sophisticated alternative therapeutic strategies. In this review, the focus is on demonstrating what has been elucidated so far about the use of next-generation probiotics as a therapeutic strategy in the treatment of individuals with PKU. The results described in the literature are encouraging and use genetically modified engineered probiotics showing efficacy both in vitro and in vivo. These probiotics appear to be suitable for meeting the unmet need for new drugs for PKU. [ABSTRACT FROM AUTHOR]