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Background: Fabry's disease, an X-linked disorder of lysosomal α-galactosidase deficiency, leads to substrate accumulation in multiple organs. Migalastat, an oral pharmacologic chaperone, stabilizes specific mutant forms of α-galactosidase, increasing enzyme trafficking to lysosomes. Methods: The initial assay of mutant α-galactosidase forms that we used to categorize 67 patients with Fabry's disease for randomization to 6 months of double-blind migalastat or placebo (stage 1), followed by open-label migalastat from 6 to 12 months (stage 2) plus an additional year, had certain limitations. Before unblinding, a new, validated assay showed that 50 of the 67 participants had mutant α-galactosidase forms suitable for targeting by migalastat. The primary end point was the percentage of patients who had a response (≥50% reduction in the number of globotriaosylceramide inclusions per kidney interstitial capillary) at 6 months. We assessed safety along with disease substrates and renal, cardiovascular, and patient-reported outcomes. Results: The primary end-point analysis, involving patients with mutant α-galactosidase forms that were suitable or not suitable for migalastat therapy, did not show a significant treatment effect: 13 of 32 patients (41%) who received migalastat and 9 of 32 patients (28%) who received placebo had a response at 6 months (P=0.30). Among patients with suitable mutant α-galactosidase who received migalastat for up to 24 months, the annualized changes from baseline in the estimated glomerular filtration rate (GFR) and measured GFR were -0.30±0.66 and -1.51±1.33 ml per minute per 1.73 m(2) of body-surface area, respectively. The left-ventricular-mass index decreased significantly from baseline (-7.7 g per square meter; 95% confidence interval [CI], -15.4 to -0.01), particularly when left ventricular hypertrophy was present (-18.6 g per square meter; 95% CI, -38.2 to 1.0). The severity of diarrhea, reflux, and indigestion decreased. Conclusions: Among all randomly assigned patients (with mutant α-galactosidase forms that were suitable or not suitable for migalastat therapy), the percentage of patients who had a response at 6 months did not differ significantly between the migalastat group and the placebo group. (Funded by Amicus Therapeutics; ClinicalTrials.gov numbers, NCT00925301 [study AT1001-011] and NCT01458119 [study AT1001-041].). [ABSTRACT FROM AUTHOR]

The article discusses a phase three clinical trial of enzyme-replacement therapy in patients with lysosomal acid lipase deficiency. The deficiency is said to be an underappreciated cause of cirrhosis and severe dyslipidemia. The trial involved 66 children and adults administered with enzyme-replacement therapy with sebelipase alfa to evaluate its safety and effectiveness. The study found that sebelipase alfa therapy reduced multiple disease-related hepatic and lipid abnormalities.

Background: Phenylketonuria is an inherited condition characterised by neurotoxic accumulation of phenylalanine (Phe). APHENITY assessed the efficacy and safety of orally administered synthetic sepiapterin in children and adults with phenylketonuria., Methods: APHENITY was a phase 3, randomised, double-blind, placebo-controlled study performed at 34 clinics, hospitals, and university sites in 13 countries. Individuals of all ages with a clinical diagnosis of phenylketonuria were eligible for inclusion if they had a blood Phe concentration of 360 μmol/L or higher at study entry, whereas individuals with hyperphenylalaninaemia due to pathogenic variants in GCH1, PTS, QDPR, SPR, and PCBD1, consistent with a diagnosis of primary BH 4 deficiency, were excluded. Part 1 was a 14-day open-label assessment of blood Phe concentration response to sepiapterin. In part 2, sepiapterin-responsive participants were randomly assigned (1:1) by a web-response system based on a block randomisation schedule (permuted block size of 2 and 4) to 6 weeks of sepiapterin (forced-dose escalation: 20, 40, and 60 mg/kg per day per consecutive 2-week period) or placebo. The investigational drug and placebo were identical in their appearance and delivery. Dried blood samples were collected for analysis of Phe concentration on days -1, 1 (before dose was administered), 5, 10, 14, 19, 24, 28, 33, 38, and 42 in part 2, either in-clinic or at home. The primary endpoint for part 2, mean change from baseline in blood Phe after 6 weeks, was assessed in the primary analysis set of participants with at least a 30% reduction in blood Phe concentration in part 1, who took at least one dose in part 2. Safety was evaluated in all participants receiving at least one dose of treatment. The completed study is registered at EudraCT (2021-000474-29) and ClinicalTrials.gov (NCT05099640)., Findings: APHENITY was conducted between Sept 30, 2021, and April 3, 2023. 187 people were assessed for eligibility, of whom 157 were enrolled. In part 1, 156 participants were assessed or evaluated, of whom 114 (73%) were sepiapterin-responsive (ie, ≥15% reduction in blood Phe from baseline). In part 2, 98 participants (49 in the placebo group and 49 in the sepiapterin group) were in the primary analysis set. There was a significant reduction of blood Phe concentration after 6 weeks of sepiapterin (-63%, SD 20) compared with placebo (1%, 29; least squares mean change -395·9 μmol/L, SE 33·8; p<0·0001). Treatment-emergent adverse events were reported in 33 (59%) of 56 participants who received sepiapterin and 18 (33%) of 54 participants who received placebo. Most treatment-emergent adverse events were mild gastrointestinal events (11 [20%] of 56 participants who received sepiapterin and ten [19%] of 54 participants who received placebo) that resolved quickly. There were no deaths and no serious or severe adverse events., Interpretation: Sepiapterin is a promising oral therapy for individuals with phenylketonuria, was well tolerated, and resulted in significant and clinically meaningful reductions in blood Phe concentration in participants with varying disease severity., Funding: PTC Therapeutics., Competing Interests: Declaration of interests ACM declares clinical trial support from BioMarin and PTC Therapeutics; participation on advisory boards for BioMarin, Jnana Therapeutics, PTC Therapeutics, and Synlogic Therapeutics; and consulting and lecturing for BioMarin, Jnana Therapeutics, and PTC Therapeutics. NL declares clinical trial support from BioMarin, Homology, Jnana Therapeutics, Moderna, and PTC Therapeutics and participation on advisory boards for Amgen/Horizon, Amicus Therapeutics, Audentes/Astellas, BioMarin, BridgeBio/CoA Therapeutic, Chiesi/Protalix, Genzyme/Sanofi, Hemoshear, Ipsen, Jaguar Gene Therapy, Jnana Therapeutics, Leadiant Biosciences, Moderna, Nestlé Pharma, PTC Therapeutics, Reneo, and Ultragenyx. IVDS declares consulting and lecturing for PTC Therapeutics. ML declares clinical trial support from BioMarin and Homology Medicines and participation on advisory boards for PTC Therapeutics and BioMarin. RZ declares research funding and advisory board involvement with PTC Therapeutics. LGu declares clinical trial support from PTC Therapeutics. AC declares clinical trial support from PTC Therapeutics. AM declares research funding from Biomarin, Nutricia, Vitaflo, Arla Ingredients, Metax, Relief Therapeutics, Cambrooke, and PTC Therapeutics. ALa, LGa, and NS are employees of PTC Therapeutics who own shares in the company. KI is an employee of PTC Therapeutics. LM, DB, FE, JCP, AB-Q, IdCCG, ALu, EK, HNM, and AG declare no competing interests. Members of the APHENITY study group declare the following competing interests: TO declares research and travel support from PTC Therapeutics; SS declares research funding and advisory board involvement with PTC Therapeutics, Biomarin, Synlogic, and Jnana Therapeutics; FR declares clinical trial support and advisory board involvement with PTC Therapeutics; HP declares clinical trial support from PTC Therapeutics and advisory board involvement with PTC Therapeutics and Biomarin; HN declares consulting and lecturing for BioMarin and clinical trial support from BioMarin, Synlogic, PTC Therapeutics, Moderna, and Jnana Therapeutics; FF declares consultancy for Biomarin, Nutricia, Vitaflo, Alexion, Recordati, Lucane, and PTC Therapeutics; SM is an employee of PTC Therapeutics and owns shares in the company; CH, RIG, and ZZ are employees of PTC Therapeutics. MAYM, MT, AK, SV, AO, and DA declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Aim: Dietary therapy of glycogen storage disease I (GSD I) is based on frequent feeding, with a high intake of complex carbohydrates (supplied by uncooked cornstarch), restriction of sugars, and a lower amount of lipids. There is limited information about the dietary regimen in patients with GSD, which might affect the intestinal luminal pH and microbiota composition. The aim of this study to investigate the intestinal microbiota composition in patients with GSD receiving diet treatment., Method: Twelve patients who were followed up with GSD I after the diagnosis receiving diet therapy and 11 healthy children have been enrolled. Intestinal microbiota composition was evaluated by 16 s rRNA gene sequencing., Results: A significant difference was found for beta-diversity between the GSD group and controls. A significantly lower abundance of Firmicutes and higher abundance of Actinobacteria was found in GSD group compared to the controls. Akkermansia, Pseudoalteromonas, Uruburella, and Castellaniella were dominant in the GSD patients at the genus level, while Faecalibacterium, Bacterioides, Gemmiger, Parabacteroides in the control group. At species level, Faecalibacterium prausnitzii decreased, and Akkermansia muciniphila were dominant in children with GSD., Discussion: There is a substantial change in the composition of the gut microbiota, reduction of F. prausnitzii and an increase of A. muciniphila in children with GSD receiving consumption of uncooked cornstarch. Alterations of the intestinal microbiota might be related with the disease itself or dietary restrictions in patients with GSD, however, in certain condition, dysbiosis can negatively affect the course and make it difficult to control the disease., (© 2024. The Author(s).)

Objectives: The mitochondrial elongation factor Tu (EF-Tu), encoded by the TUFM gene, is a GTPase, which is part of the mitochondrial protein translation mechanism. If it is activated, it delivers the aminoacyl-tRNAs to the mitochondrial ribosome. Here, a patient was described with a homozygous missense variant in the TUFM [c.1016G>A (p.Arg339Gln)] gene. To date, only six patients have been reported with bi-allelic pathogenic variants in TUFM, leading to combined oxidative phosphorylation deficiency 4 (COXPD4) characterized by severe early-onset lactic acidosis, encephalopathy, and cardiomyopathy., Case Presentation: The patient presented here had the phenotypic features of TUFM-related disease, lactic acidosis, hypotonia, liver dysfunction, optic atrophy, and mild encephalopathy., Conclusions: We aimed to expand the clinical spectrum of pathogenic variants of TUFM., (© 2024 Walter de Gruyter GmbH, Berlin/Boston.)

Objectives: Gaucher disease (GD) is a lysosomal storage disease caused by glucocerebrosidase (GCase) enzyme deficiency. Gaucher cells transformed from the macrophages by progressive sphingolipid accumulation and infiltrate bone marrow, spleen, liver, and other organs. The accumulation of substrate causes inflammation, compromised cellular homeostasis, and disturbed autophagy. It has been hypothesized that this proinflammatory state of GD leads cytokines and chemokines release. As a result of inflammatory process, the cellular dysfunction caused by disruption of cellular signaling, organelle dysfunction, or autoimmune antibodies may affect endocrine profile of GD patients such as hormone levels, lipid profile, and bone mineral density status., Methods: A total of 13 patients confirmed to have GD, 12 non-neuronopathic type and one subacute neuronopathic type, were enrolled in our study., Results: The median treatment duration in the enzyme therapy was 13.33 years (9-26 years). At least one endocrinological abnormality was detected in blood tests of nine patients. Hyperinsulinism was the most common finding although fasting blood glucose levels HgbA1c levels were normal in all patients. Two patients had osteopenia, and osteoporosis was detected in two patients. Low HDL levels were detected in six patients, but HDL levels below 23 mg/dL associated with disease severity have been detected in two patients who have not receiving enzyme replacement therapy. None of patients had thyroidal dysfunction., Conclusions: This study had revealed endocrinological abnormalities in GD patients that have not led any severe morbidity in our patients. However, thyroid hormone abnormalities, insulin resistance, or lipid profile abnormalities may cause unpredictable comorbidities. Endocrinological assessment in GD patients in routine follow-up may prevent possible clinical manifestation in long term as well as can define efficacy of ERT on endocrine abnormalities., (© 2024 Walter de Gruyter GmbH, Berlin/Boston.)

This review by a panel of pediatric metabolic disease specialists aimed to provide a practical and implementable guidance document to assist clinicians in best clinical practice in terms of recognition, diagnosis and management of patients with acid sphingomyelinase deficiency (ASMD). The participating experts consider the clinical suspicion of ASMD by the physician to be of utmost importance in the prevention of diagnostic delay and strongly suggest the use of a diagnostic algorithm including/starting with dried blood spots assay in the timely diagnosis of ASMD in patients presenting with hepatosplenomegaly and a need for increased awareness among physicians in this regard to consider ASMD in the differential diagnosis. In anticipation of the introduction of enzyme replacement therapy, raising awareness of the disease among physicians to prevent diagnostic delay and further investigation addressing natural history of ASMD across the disease spectrum, potential presenting characteristics with a high index of suspicion, as well as biomarkers and genotype-phenotype correlations suggestive of poor prognosis seem important in terms of implementation of best practice patterns., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Arslan, Coker, Gokcay, Kiykim, Onenli Mungan and Ezgu.)

Objectives: Fabry disease is an X-linked lysosomal disorder caused by decreased or absent alpha galactosidase enzyme. The enzyme deficiency leads to progressive accumulation of globotriaosylceramide (Gb-3) and its deacetylated form lyso-Gb3 in various tissue lysosomes that results in primarily lysosomal deterioration and subsequently mitochondrial, endothelial, and immunologic dysfunctions., Methods: The endocrinological, metabolic, immunological and HLA status of 12 patients were evaluated., Results: A total of 11 patients (91.6 %) had immunologic and/or endocrinologic abnormalities. fT4, anti-TPO, and anti-TG levels were increased in 1, 2, and 2 patients, respectively. Three patients had elevated proinflammatory cytokines. ANA profile, p-ANCA and c-ANCA were positive in 1, 1, and 2 patients, respectively. Tissue transglutaminase antibody was negative in all patients however P5 was diagnosed with Celiac disease at the age of 12 and on gluten free diet. All patients had distinct types of HLA apart from 2 patients with anti-TG and anti-TPO positive and there was no relationship between the HLA types and the autoimmunity biomarkers., Conclusions: FD may have impact on endocrinologic and immunologic abnormalities even in the patients under ERT, therefore prevalence of these abnormalities may be higher in ERT naïve patients. However, apparently, they are less likely to cause clinical symptoms. Certain HLA alleles may contribute to the direct impact of immunological pathogenesis in FD by developing abnormal autoimmune biomarkers. To the best of our knowledge, this is the first study investigating HLA status of FD patients; therefore further studies are needed to elucidate the underlying mechanism of action., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

This expert-opinion-based document was prepared by a group of specialists in pediatric inherited metabolic diseases and infectious diseases including administrative board members of Turkish Society for Pediatric Nutrition and Metabolism to provide guidance for the care of children with lysosomal storage disorders (LSDs) during the COVID-19 pandemic in Turkey. The experts reached consensus on key areas of focus regarding COVID-19-based risk status in relation to intersecting immune-inflammatory mechanisms and disease patterns in children with LSDs, diagnostic virus testing, particularly preventive measures and priorities during the pandemic, routine screening and diagnostic interventions for LSDs, psychological and socioeconomic impact of confinement measures and quarantines and optimal practice patterns in managing LSDs and/or COVID-19. The participating experts agreed on the intersecting characteristics of immune-inflammatory mechanisms, end-organ damage and prognostic biomarkers in LSD and COVID-19 populations, emphasizing the likelihood of enhanced clinical care when their interaction is clarified via further studies addressing certain aspects related to immunity, lysosomal dysfunction and disease pathogenesis. In the context of the current global COVID-19 pandemic, this expert-opinion-based document provides guidance for the care of children with LSDs during the COVID-19 pandemic based on the recent experience in Turkey., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Akgun, Gokcay, Mungan, Sivri, Tezer, Zeybek and Ezgu.)

BackgroundSanfilippo type B is a mucopolysaccharidosis (MPS) with a major neuronopathic component characterized by heparan sulfate (HS) accumulation due to mutations in the NAGLU gene encoding alfa-N-acetyl-glucosaminidase. Enzyme replacement therapy for neuronopathic MPS requires efficient enzyme delivery throughout the brain in order to normalize HS levels, prevent brain atrophy, and potentially delay cognitive decline.MethodsIn this phase I/II open-label study, patients with MPS type IIIB (n = 22) were treated with tralesinidase alfa administered i.c.v. The patients were monitored for drug exposure; total HS and HS nonreducing end (HS-NRE) levels in both cerebrospinal fluid (CSF) and plasma; anti-drug antibody response; brain, spleen, and liver volumes as measured by MRI; and cognitive development as measured by age-equivalent (AEq) scores.ResultsIn the Part 1 dose escalation (30, 100, and 300 mg) phase, a 300 mg dose of tralesinidase alfa was necessary to achieve normalization of HS and HS-NRE levels in the CSF and plasma. In Part 2, 300 mg tralesinidase alfa sustained HS and HS-NRE normalization in the CSF and stabilized cortical gray matter volume (CGMV) over 48 weeks of treatment. Resolution of hepatomegaly and a reduction in spleen volume were observed in most patients. Significant correlations were also established between the change in cognitive AEq score and plasma drug exposure, plasma HS-NRE levels, and CGMV.ConclusionAdministration of tralesinidase alfa i.c.v. effectively normalized HS and HS-NRE levels as a prerequisite for clinical efficacy. Peripheral drug exposure data suggest a role for the glymphatic system in altering tralesinidase alfa efficacy.Trial registrationClinicaltrials.gov NCT02754076.FUNDINGBioMarin Pharmaceutical Inc. and Allievex Corporation.

Objective: To characterize the longitudinal natural history of disease progression in pediatric subjects affected with mucopolysaccharidosis (MPS) IIIB., Study Design: Sixty-five children with a confirmed diagnosis of MPS IIIB were enrolled into 1 of 2 natural history studies and followed for up to 4 years. Cognitive and adaptive behavior functions were analyzed in all subjects, and volumetric magnetic resonance imaging analysis of liver, spleen, and brain, as well as levels of heparan sulfate (HS) and heparan sulfate nonreducing ends (HS-NRE), were measured in a subset of subjects., Results: The majority of subjects with MPS IIIB achieved an apex on both cognition and adaptive behavior age equivalent scales between age 3 and 6 years. Development quotients for both cognition and adaptive behavior follow a linear trajectory by which subjects reach a nadir with a score <25 for an age equivalent of 24 months by age 8 years on average and by 13.5 years at the latest. All tested subjects (n = 22) had HS and HS-NRE levels above the normal range in cerebrospinal fluid and plasma, along with signs of hepatomegaly. Subjects lost an average of 26 mL of brain volume (-2.7%) over 48 weeks, owing entirely to a loss of cortical gray matter (32 mL; -6.5%)., Conclusions: MPS IIIB exists along a continuum based on cognitive decline and cortical gray matter atrophy. Although a few individuals with MPS IIIB have an attenuated phenotype, the majority follow predicted trajectories for both cognition and adaptive behavior., Trial Registration: ClinicalTrials.gov identifiers NCT02493998, NCT03227042, and NCT02754076., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

This consensus statement by a panel of Fabry experts aimed to identify areas of consensus on conceptual, clinical and therapeutic aspects of Fabry disease (FD) and to provide guidance to healthcare providers on best practice in the management of pediatric and adult patients with FD. This consensus statement indicated the clinical heterogeneity of FD as well as a large number of pathogenic variants in the GLA gene, emphasizing a need for an individualized approach to patient care. The experts reached consensus on the critical role of a high index of suspicion in symptomatic patients and screening of certain at-risk groups to reveal timely and accurate diagnosis of FD along with an increased awareness of the treating physician about the different kinds of pathogenic variants and their clinical implications. The experts emphasized the crucial role of timely recognition of FD with minimal delay from symptom onset to definite diagnosis in better management of FD patients, given the likelihood of changing the disease's natural history, improving the patients' quality of life and the prognosis after enzyme replacement therapy (ERT) administered through a coordinated, multidisciplinary care approach. In this regard, this consensus document is expected to increase awareness among physicians about unique characteristics of FD to assist clinicians in recognizing FD with a well-established clinical suspicion consistent with pathogenic variants and gender-based heterogeneous clinical manifestations of FD and in translating this information into their clinical practice for best practice in the management of patients with FD., (© 2022. The Author(s).)

Objectives: Fructose 1,6 bisphosphatase (FBPase) deficiency is a rare autosomal recessively inherited metabolic disease. It is encoded by FBP1 , and the enzyme catalyzes the hydrolysis of fructose-1,6-bisphosphate to fructose 6-phosphate. Patients with recurrent episodes of metabolic acidosis, hypoglycemia, hypertriglyceridemia, and hyperketonemia are present., Methods: In this study, we describe the clinical, biochemical, and molecular genetic features of six unrelated Turkish patients from six different families who were genetically diagnosed with FBPase deficiency in our clinic between 2008 and 2020. Their clinical and laboratory data were collected retrospectively. Next-generation sequencing (NGS) was performed for the molecular genetic analysis., Results: All patients were hospitalized with recurrent hypoglycemia and metabolic acidosis episodes. Three out of six patients were presented in the neonatal period. The mean age at diagnosis was 26 months. NGS revealed a known homozygous gross deletion including exon 2 in three patients (50%), a known homozygous c.910&#95;911dupTT pathogenic variant in one patient (16%), a novel homozygous c.651&#95;653delCAGinsTAA likely pathogenic variant, and another novel homozygous c.705+5G>A splice site variant. Leukocyte FBPase analysis detected no enzyme activity in the patient with homozygous c.705+5G>A splice site variant., Conclusions: We identified two novel mutations in this study. One of them is a splice site mutation which is five bases downstream of the exon, and the other one is an indel mutation. Both of the splice site and indel mutations are exceedingly rare in FBP1 , and to the best of our knowledge, there are second splice site and indel variants reported in the literature. Exon 2 deletion is the most common mutation consistent with the previous reports in Turkish patients. FBPase is a frequent cause of hypoglycemia and metabolic acidosis, and the widespread use of molecular genetic analysis would contribute to the enlightenment of advanced genetic factors and possible genotype/phenotype correlation., (© 2022 Walter de Gruyter GmbH, Berlin/Boston.)

Background: Cystic fibrosis, a pulmonary disease which is an autosomal recessive, inherited, multisystemic genetic disease commonly seen in the Caucasian race, is the most frequent cause of mortality and morbidity. So far, more than 2000 disease-causing gene variants have been found and this number has been increasing with the studies conducted. Although there is not yet enough data that include the Turkish population, the recent increase of studies is noteworthy., Aims: To discover the genetic variation in patients diagnosed with cystic fibrosis in the Central Anatolian region., Study Design: Cross-sectional study., Methods: The study was carried out in the Central Anatolian region in 3 pediatric pulmonology departments (Kayseri, Konya, and Ankara) in Turkey between July 2014 and December 2017. The Sanger and Next Generation Sequence analyses were used for exon and exon-intron boundaries in the cystic fibrosis transmembrane conductance regulatory (CFTR) gene, and in selected patients, mutation analysis was performed using the Multiplex Ligation-dependent Probe Amplification technique for large deletions and duplications., Results: CFTR gene analysis was performed for 316 patients and 215 of them were genetically diagnosed with cystic fibrosis. Sixtythree different variants were defined in these patients and 7 of these were large deletions/duplications detected with the MLPA method. The most frequent variants were F508del (29.6%), G85E (8.2%), N1303K (8.2%), Y515* (7.5%), and G542* (3.4%)., Conclusion: Using sequencing and Multiplex Ligation-dependent Probe Amplification methods, the identification of seven new mutations that were not previously reported in the literature contributes to a better understanding of the heterogeneous nature of CFTR mutations in the Turkish population. When no mutations are detected (pathogenic/probably pathogenic) in clinically compatible cases, Multiplex Ligationdependent Probe Amplification analysis contributes significantly to the diagnosis.

The pathophysiology of congenital defects of glycosylation (CDG) is complex and the diagnosis has been a challenge because of the overlapping clinical signs and symptoms as well as a large number of disorders. Isoelectric focusing of transferrin has been used as a screening method but has limitations. Individual enzyme or molecular genetic tests have been difficult to perform. In this study, we aimed to describe CDG patients who were referred to from different departments either without a preliminary diagnosis or suspected to have a genetic disorder other than CDG. The patients were diagnosed mainly with a 450 gene next-generation DNA sequencing panel for inborn errors of metabolism, which also included 25 genes for CDG. A total of 862 patients were investigated with the panel, whereby homozygous (10) or compound heterozygous (4) mutations were found in a total of 14 (1.6%) patients. A total of 13 different mutations were discovered, 10 of them being novel. Interestingly, none of the patients was suspected to have a CDG before referral. This report expands the clinical/laboratory findings in patients with CDG and stresses on the fact that CDG should be in the differential list for pediatric patients presented with nonspecific dysmorphic features and neurological delays/regression. Also, next-generation DNA sequencing with panel approach was noticed to have a significant diagnostic potential in patients presented with nonspecific neurologic and dysmorphic findings., (© 2021 Wiley Periodicals LLC.)

Background: Glycogen storage disease (GSD) type IXb is one of the rare variants of GSDs. It is a genetically heterogeneous metabolic disorder due to deficient hepatic phosphorylase kinase activity. Diagnosis of GSD can be difficult because of overlapping manifestations. Mutation analysis of the genes related to each type of GSD is supposed to be problem-solving, however, the presence of novel mutations can be confusing. In this case report, we will describe our experience with a young girl with the diagnosis of GSD and two novel mutations related to GSD type IXb., Case Presentation: A 3-year- old girl presented with short stature, hepatomegaly, and liver cirrhosis. No specific diagnosis was made based on laboratory data, so liver biopsy and targeted-gene sequencing (TGS) were performed to find out the specific molecular basis of her disease. It was confirmed that the patient carries two novel variants in the PHKB gene. The variant in the PHKB gene was classified as pathogenic., Conclusions: This is the first reported case of a dual molecular mutation of glycogen storage disease type IXb in the same patient. Two novel variants in PHKB were identified and one of them was a pathogenic split-site mutation. In conclusion, for the first time, identification of the novel variants in this patient expands the molecular and the phenotype basis of dual variants in GSD-IXb.

Glycogen storage diseases (GSDs) are known as complex disorders with overlapping manifestations. These features also preclude a specific clinical diagnosis, requiring more accurate paraclinical tests. To evaluate the patients with particular diagnosis features characterizing GSD, an observational retrospective case study was designed by performing a targeted gene sequencing (TGS) for accurate subtyping. A total of the 15 pediatric patients were admitted to our hospital and referred for molecular genetic testing using TGS. Eight genes namely SLC37A4, AGL, GBE1, PYGL, PHKB, PGAM2, and PRKAG2 were detected to be responsible for the onset of the clinical symptoms. A total number of 15 variants were identified i.e. mostly loss-of-function (LoF) variants, of which 10 variants were novel. Finally, diagnosis of GSD types Ib, III, IV, VI, IXb, IXc, X, and GSD of the heart, lethal congenital was made in 13 out of the 14 patients. Notably, GSD-IX and GSD of the heart-lethal congenital (i.e. PRKAG2 deficiency) patients have been reported in Iran for the first time which shown the development of liver cirrhosis with novel variants. These results showed that TGS, in combination with clinical, biochemical, and pathological hallmarks, could provide accurate and high-throughput results for diagnosing and sub-typing GSD and related diseases.

Background: Mutations in the PRKAG2 gene encoding the 5' Adenosine Monophosphate-Activated Protein Kinase (AMPK), specifically in its γ2 regulatory subunit, lead to Glycogen storage disease of heart, fetal congenital disorder (PRKAG2 syndrome). These mutations are rare, and their functional roles have not been fully elucidated. PRKAG2 syndrome is autosomal dominant disorder inherited with full penetrance. It is characterized by the accumulation of glycogen in the heart tissue, which is clinically manifested as hypertrophic cardiomyopathy. There is little knowledge about the characteristics of this disease. This study reports a genetic defect in an Iranian family with liver problems using targeted-gene sequencing., Case Presentation: A 4-year-old girl presented with short stature, hepatomegaly, and liver cirrhosis. As there was no specific diagnosis made based on the laboratory data and liver biopsy results, targeted-gene sequencing (TGS) was performed to detect the molecular basis of the disease. It was confirmed that this patient carried a novel heterozygous variant in the PRKAG2 gene. The echocardiography was a normal., Conclusion: A novel heterozygous variant c.592A > T (p.Met198Leu) expands the mutational spectrum of the PRKAG2 gene in this family. Also, liver damage in patients with PRKAG2 syndrome has never been reported, which deserves further discussion.

Objectives: The PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease (PREDICT-FD) initiative aimed to reach consensus among a panel of global experts on early indicators of disease progression that may justify FD-specific treatment initiation., Design and Setting: Anonymous feedback from panellists via online questionnaires was analysed using a modified Delphi consensus technique. Questionnaires and data were managed by an independent administrator directed by two non-voting cochairs. First, possible early indicators of renal, cardiac and central/peripheral nervous system (CNS/PNS) damage, and other disease and patient-reported indicators assessable in routine clinical practice were compiled by the cochairs and administrator from panellists' free-text responses. Second, the panel scored indicators for importance (5-point scale: 1=not important; 5=extremely important); indicators scoring ≥3 among >75% of panellists were then rated for agreement (5-point scale: 1=strongly disagree; 5=strongly agree). Indicators awarded an agreement score ≥4 by >67% of panellists achieved consensus. Finally, any panel-proposed refinements to consensus indicator definitions were adopted if >75% of panellists agreed., Results: A panel of 21 expert clinicians from 15 countries provided information from which 83 possible current indicators of damage (kidney, 15; cardiac, 15; CNS/PNS, 13; other, 16; patient reported, 24) were compiled. Of 45 indicators meeting the importance criteria, consensus was reached for 29 and consolidated as 27 indicators (kidney, 6; cardiac, 10; CNS/PNS, 2; other, 6; patient reported, 3) including: (kidney) elevated albumin:creatinine ratio, histological damage, microalbuminuria; (cardiac) markers of early systolic/diastolic dysfunction, elevated serum cardiac troponin; (CNS/PNS) neuropathic pain, gastrointestinal symptoms suggestive of gastrointestinal neuropathy; (other) pain in extremities/neuropathy, angiokeratoma; (patient-reported) febrile crises, progression of symptoms/signs. Panellists revised and approved proposed chronologies of when the consensus indicators manifest. The panel response rate was >95% at all stages., Conclusions: PREDICT-FD captured global opinion regarding current clinical indicators that could prompt FD-specific treatment initiation earlier than is currently practised., Competing Interests: Competing interests: DAH: advisory boards for Amicus, Sanofi, Shire (now part of Takeda); consulting fees from Amicus, Idorsia, Sanofi and Shire (now part of Takeda); honoraria from Amicus, Sanofi and Shire (now part of Takeda). PA: research grant and honoraria from Shire (now part of Takeda); honoraria from Amicus, Biomarin, Sanofi and Ultragenyx. PBD: speaker honoraria from and advisory boards for Takeda and Sanofi; consultancy for Sanofi. FE: travel grants and speaker honoraria from Pfizer, Sanofi Genzyme and Takeda. AF: research grants from Amicus and Shire. OL: travel grants and speaker honoraria from Amicus, Sanofi Genzyme and Shire HGT. AL: speaker’s honoraria or consultation fees from Amicus, Sanofi Genzyme and Takeda. J-CL: speaker’s honoraria and consultation fees from Shire. JCM: research grant and speaker honoraria from Sanofi Genzyme; advisory board for, and honoraria from ST; consulting fees from 4DMT. KN: research support and/or honoraria from Amicus, Idorsia, Protalix, Sanofi and Shire (now part of Takeda); advisory boards for Amicus, Sanofi and Shire (now part of Takeda). D-MN: research funding from Shire (now part of Takeda) and Sanofi. AN: honoraria and research support from Sanofi Genzyme and Shire (now part of Takeda). UR: advisory boards for Amicus, Chiesi, Idorsia and Shire; travel grants and honoraria from Amicus, Genzyme and Shire. RR: travel grants and speaker honoraria from Amicus and Shire HGT (now part of Takeda). PR: advisory board, consulting fees and research grant from Shire (now part of Takeda). RS: advisory boards for Amicus, Sanofi, Shire (now part of Takeda); honoraria from Amicus and Shire; research funding from Idorisia, Protalix, Sanofi Genzyme and Takeda. ES: speaker’s fees and travel support from Amicus, Sanofi Genzyme and Shire; advisory board honoraria from Amicus and Sanofi Genzyme. MT: advisory boards for Amicus, Sanofi and Shire (now part of Takeda); travel grants and speaker’s honoraria from Amicus, Sanofi and Shire; research funding from Amicus, AVROBIO and Idorsia. RT: travel grants, speaker’s honoraria or consultation fees from Amicus, Sanofi Genzyme and Takeda. BV: speaker’s fees and travel support from Greenovation, Sanofi Genzyme and Shire/Takeda; advisory board honoraria from Sanofi Genzyme. DGW: advisory boards for Amicus, Avrobio, Freeline Therapeutics, 4D-MT Technology, Idorsia and Protalix; honoraria and travel expenses from Amicus, Protalix and Sanofi; and equity interest in Reata Pharmaceuticals. MLW: advisory boards for Amicus, Sanofi and Shire (now part of Takeda); honoraria from Amicus, Sanofi and Shire; research funding from Amicus, Idorisia, Protalix and Shire. JJ: honoraria from Sanofi; travel expenses from Amicus and Sanofi. MJR is an employee of Oxford PharmaGenesis (Oxford, UK). SF: advisory boards for Amicus; consulting fees from Shire (now part of Takeda); contracted research from Shire (now part of Takeda); honoraria from Amicus, Sanofi and Shire (now part of Takeda); speaker’s bureau for Amicus, Sanofi and Shire (now part of Takeda); travel expenses from Amicus, Sanofi and Shire (now part of Takeda)., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To evaluate vitamin D levels and bone mineral density in patients with dietary limitations due to inborn errors of metabolism (IEM) and its correlation with diets., Study Design: Retrospective study., Place and Duration of Study: Department of Pediatrics, Division of Pediatric Metabolism and Nutrition, Gazi University Hospital, Turkey, from March to Semtember 2016., Methodology: The study is a retrospective review of 115 patients. Information about vitamin D status, bone mineral density (BMD) measurement and anthropometric parametres were collected. Patients were divided into two major groups, receiving protein-restricted diets (n=83) and lactose-restricted diets (n=32). Data of 110 healthy children were used as the control group., Results: Mean vitamin D level of patients with special diets 28.1 ±14.9 ng/ml while mean level of healthy controls was 26.6 ±12.27 ng/ml. Levels of 26.8% (n=26/97) patients were found to be deficient and 34% (n=33/97) were found to be insufficient. No statistically significant differences were found between vitamin D levels and BMD of patients and healthy controls. BMD was not influenced by vitamin D levels., Conclusion: Low BMD may be encountered in IEM, independent of vitamin D levels and revision of diet for adequacy of essential nutrients; and follow-up for dietary compliance is inevitable.

Background: Infants presenting with lysosomal acid lipase deficiency have marked failure to thrive, diarrhea, massive hepatosplenomegaly, anemia, rapidly progressive liver disease, and death typically in the first 6 months of life; the only available potential treatment has been hematopoietic stem cell transplantation, which is associated with high morbidity and mortality in this population. The study objective was to evaluate safety and efficacy (including survival) of enzyme replacement with sebelipase alfa in infants with lysosomal acid lipase deficiency. This is an ongoing multicenter, open-label, phase 2/3 study conducted in nine countries. The study enrolled infants with growth failure prior to 6 months of age with rapidly progressive lysosomal acid lipase deficiency; they received once-weekly doses of sebelipase alfa initiated at 0.35 mg/kg with intrapatient dose escalation up to 5 mg/kg. The main outcome of interest is survival to 12 months and survival beyond 24 months of age., Results: Nine patients were enrolled; median age at baseline was 3.0 months (range 1.1-5.8 months). Sixty-seven percent (exact 95% CI 30%-93%) of sebelipase alfa-treated infants survived to 12 months of age compared with 0% (exact 95% CI 0%-16%) for a historical control group (n = 21). Patients who survived to age 12 months exhibited improvements in weight-for-age, reductions in markers of liver dysfunction and hepatosplenomegaly, and improvements in anemia and gastrointestinal symptoms. Three deaths occurred early (first few months of life), two patients died because of advanced disease, and a third patient died following complications of non-protocol-specified abdominal paracentesis. A fourth death occurred at 15 months of age and was related to other clinical conditions. The five surviving patients have survived to age ≥24 months with continued sebelipase alfa treatment; all have displayed marked improvement in growth parameters and liver function. Serious adverse events considered related to sebelipase alfa were reported in one of the nine infants (infusion reaction: tachycardia, pallor, chills, and pyrexia). Most infusion-associated reactions were mild and non-serious., Conclusion: Sebelipase alfa markedly improved survival with substantial clinically meaningful improvements in growth and other key disease manifestations in infants with rapidly progressive lysosomal acid lipase deficiency TRIAL REGISTRATION: Clinicaltrials.gov NCT01371825 . Registered 9 June 2011.

Inborn errors of metabolism are single gene disorders resulting from the defects in the biochemical pathways of the body. Although these disorders are individually rare, collectively they account for a significant portion of childhood disability and deaths. Most of the disorders are inherited as autosomal recessive whereas autosomal dominant and X-linked disorders are also present. The clinical signs and symptoms arise from the accumulation of the toxic substrate, deficiency of the product, or both. Depending on the residual activity of the deficient enzyme, the initiation of the clinical picture may vary starting from the newborn period up until adulthood. Hundreds of disorders have been described until now and there has been a considerable clinical overlap between certain inborn errors. Resulting from this fact, the definite diagnosis of inborn errors depends on enzyme assays or genetic tests. Especially during the recent years, significant achievements have been gained for the biochemical and genetic diagnosis of inborn errors. Techniques such as tandem mass spectrometry and gas chromatography for biochemical diagnosis and microarrays and next-generation sequencing for the genetic diagnosis have enabled rapid and accurate diagnosis. The achievements for the diagnosis also enabled newborn screening and prenatal diagnosis. Parallel to the development the diagnostic methods; significant progress has also been obtained for the treatment. Treatment approaches such as special diets, enzyme replacement therapy, substrate inhibition, and organ transplantation have been widely used. It is obvious that by the help of the preclinical and clinical research carried out for inborn errors, better diagnostic methods and better treatment approaches will high likely be available., (© 2016 Elsevier Inc. All rights reserved.)

Early diagnosis for metabolic encephalopathy caused by inborn errors of metabolism is very important for the initiation of early treatment and also for prevention of sequela. Metabolic encephalopathy in the form of seizures can result from many inborn errors of metabolism and considering the large number of disorders causing metabolic encephalopathy, enzyme assays or conventional molecular tests are expensive and take considerably long period of time which results in delayed treatment. In our center we have used next generation DNA sequencing technology as an initial diagnostic test to look for about 700 disorders at the same time for the etiologic diagnosis of a 4-month-old female infant suffering from intractable seizures. The patient was found to have glycine encephalopathy resulting from a previously defined mutation in the GLDC gene. The diagnostic result was obtained much sooner than other conventional investigations. Up to our knowledge, this would be the first case with glycine encephalopathy in the literature who was approached by this novel panel method initially. Although currently, classical evaluation methods such as physical examination, biochemical and conventional molecular investigations are still accepted as the gold standards to clarify the etiology of the metabolic encephalopathy it is obvious that next generation sequence analysis will play a very significant role in the future.

For inborn errors of metabolism, high resolution melting analysis (HRMA) is a rapid, efficient, simple, and inexpensive method for mutation/rare variant screening. HRMA is a recent molecular technique for genotyping single-nucleotide polymorphisms without using probes. Here we apply HRMA to the α-galactosidase a (GLA) and glucose-6-phosphatase-alpha (G6PC) genes for mutation detection of patients with Fabry disease (MIM 301500) and glycogen storage disease type 1A (GSD1A; MIM 232200), respectively. To evaluate the procedure, genomic DNAs were blindly tested for known GLA mutations (c.658C>T, c. 679C>T, c.772G>A, c.796G>A, or c.718-719delAA) in three affected males and two obligate heterozygotes with Fabry disease, a G6PC mutation (c.247C>T) in a patient homozygous for that lesion, and 10 healthy control Turkish individuals. HRMA clearly detected the mutant amplicons and discriminated them from all wild-type GLA or G6PC amplicons. HRMA proved to be a sensitive, specific, and cost-effective mutation screening method for the rapid molecular diagnosis of these inborn errors of metabolism, indicating that the technique can be readily adapted to other genetic diseases.

Very early onset Toni-Debré-Fanconi Syndrome, a disorder of proximal renal tubules of the kidney which results in the increased urinary excretion of glucose, amino acids, uric acid, phosphate and bicarbonate, could be the manifestation of various inborn errors. Defects of oxidative phosphorylation are a heterogeneous group of disorders with various clinical presentations. Recently, patients with early liver failure, renal tubulopathy and encephalopathy due to the mutations in the BCS1L gene coding for a structural protein in mitochondrial complex III have been described. Ten-day-old female newborn was referred to our clinic because of intractable acidosis. Physical examination revealed severe hypotonia, and hepatomegaly. The laboratory examinations revealed lactic acidosis, increased blood alanine, alanine aminotransferase and aspartate aminotransferase levels, generalized aminoaciduria and glucosuria. The tubular reabsorption of phosphate was reduced. Because of multisystem involvement, mitochondrial disease was suspected and the mutational analysis of the BCS1L gene revealed homozygous P99L mutation. As the patient was unresponsive to bicarbonate replacement, oral dichloroacetate and peritoneal dialysis, continuous high dose intravenous sodium bicarbonate therapy with a dose up to 1.25 mEq/kg/h was started. The patient got on well until the age of 9 months when she died of sepsis. It was stressed that high dose intravenous continuous sodium bicarbonate therapy could be an alternative treatment option in patients with severe acidosis and renal tubulopathy resistant to dichloroacetate and peritoneal dialysis. Patients with BCS1L mutations should be considered in the differential diagnosis of severe tubulopathy in the newborn period., (© 2013.)

Background: Chronic renal failure (CRF) is a serious complication of Fabry disease (FD). The aims of the present study were to determine the prevalence of unrecognized FD in Turkish hemodialysis population and to investigate the molecular background., Method: Primarily, α-galactosidase A (α-Gal A) activity was investigated on DBS in 1136 patients of both sexes who underwent dialysis for CRF in Turkey. The disease was confirmed by analyzing enzyme activity in leukocyte and GLA gene sequencing in all patients in whom α-Gal A level was 40% of normal or less., Results: Mean age of the patients (44.5% female, 52.5% male) was 56.46±15.85 years. Enzyme activity was found low with DBS method in 12 patients (four males, eight females). Two men, but no women, were diagnosed with FD by enzymatic and molecular analysis. In consequence of genetic analysis of a case, a new mutation [hemizygote c.638C>T (p.P214S) missense mutation in exon 5] was identified, which was not described in literature. Family screening of cases identified six additional cases., Conclusion: As a result of this initial screening study performed on hemodialysis patients for the first time with DBS method in Turkey, the prevalence of FD was detected as 0.17%. Although the prevalence seems to be low, screening studies are of great importance for detecting hidden cases as well as for identifying other effected family members., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Mutations in the FH gene cause the deficiency of the enzyme fumarase (fumarate hydratase, EC 4.2.1.2) which result in autosomal recessive fumaric aciduria in early childhood with failure to thrive, seizures, developmental delay, mental retardation, hypotonia and sometimes with polycythemia, leukopenia, and neutropenia. Many children with fumarate hydratase deficiency do not survive infancy or childhood; those surviving beyond childhood have severe psychomotor retardation. Recently, FH gene was also identified as a "non-classical" tumor suppressor gene and heterozygous mutations were shown to cause multiple cutaneous and uterine leiomyomas as well as hereditary leiomyomatosis and renal cell cancer. A male patient who was referred to investigate the etiology of psychomotor retardation was later diagnosed to have fumaric aciduria due to the combination of a previously known (c.1431&#95;1433dupAAA) and a novel (c.782G>T) mutation. The patient had an unusually mild clinical course without acidotic attacks. Interestingly his father who was heterozygous for the c.1431&#95;1433dupAAA mutation in the FH gene had cutaneous leiomyoma., (Copyright © 2013 Elsevier B.V. All rights reserved.)