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Hypophosphatasia (HPP) is characterized by low activity of tissue nonspecific alkaline phosphatase (TNSALP). The enzyme replacement therapy asfotase alfa has been approved for childhood-onset forms of HPP. MicroRNAs (miRNAs) have emerged as a novel disease biomarker, with potential application in therapy monitoring. Circulating miRNAs were analyzed at baseline, months 1, 2, 4, and 16 in a 49-yr-old woman with childhood-onset HPP, chronic musculoskeletal pain, and non-traumatic fractures prior to enzyme replacement therapy. Serum RNA was extracted and sequenced using miRNeasy Mini Kit (Qiagen, Germany), RealSeq Biosciences Kit (Santa Cruz, US) together with miND spike-in control kit (TAmiRNA, Austria) and Illumina NovaSeq 6000 SP1 flow cell (San Diego, US). Brief Pain Inventory Severity and Interference scores (BPI-S/BPI-I), fatigue severity scale (FSS), Patient Global Impression of Improvement (PGI-I), Western Ontario and McMaster university hip disability and osteoarthritis outcome score (WOMAC), fibromyalgia impact questionnaire (FIQ), 6-Minute Walking Test (6-MWT), chair-rise-test (CRT), and handgrip dynamometry (HD) were performed at baseline and different timepoints during the therapy. Out of >800 screened, 84 miRNAs were selected based on differences in expression profiles between 24 HPP patients and 24 healthy controls. Six miRNAs showed a clear graphic trend and were up- or downregulated by ≥50% reads per million (rpm). These included hsa-let-7i-5p (+50%), hsa-miR-1-3p (−66.66%), hsa-miR-1294 (+63.63%), hsa-miR-206 (−85.57%), hsa-miR-375-3p (−71.43%), and hsa-miR-624-5p (+69.44%). hsa-miR-1-3p and hsa-miR-206 were identified as muscle-specific miRNAs. hsa-mir-375-3p, which negatively regulates osteogenesis, was significantly downregulated. In terms of patient-reported outcomes, BPI-S, BPI-I, FSS, PGI-I, WOMAC, and FIQ showed a reduction by −58.62%, −68.29%, −33.33%, −75.00%, −63.29%, and −43.02%, respectively. 6-MWT improved by +33.89% and CRT by −44.46%. Mean hand grip strength of the right/left hand measured by HD improved by +12.50% and + 23.53%, respectively. miRNA profile changes during the therapy with asfotase alfa, accompanying improvements in functionality tests and quality of life scores. Lay Summary: Hypophosphatasia (HPP) is a rare genetic bone disease characterized by low activity of an enzyme involved in mineralization of bony tissues, the nonspecific alkaline phosphatase (TNSALP). The enzyme replacement therapy with recombinant asfotase alfa has been approved recently. MicroRNAs (miRNAs) are small signaling molecules, which are involved in the regulation of gene expression and signaling pathways. They emerged as a novel disease biomarker, with potential application in therapy monitoring. We analyzed the levels of miRNAs of a 49-yr-old woman with childhood-onset HPP during the therapy. The patient suffered from musculoskeletal pain and non-traumatic fractures before the begin of enzyme replacement therapy. miRNAs in blood and clinical tests were performed at baseline and different timepoints. Blood levels of 6 miRNAs showed a clear graphic trend and were elevated or lowered by ≥50% units (reads per million) during the therapy. Patient-reported questionnaires showed a reduction of at least a third, reflecting clinical improvement of symptoms during the therapy. The scores of 6-MWT and CRT and hand grip also improved, signaling improvements in muscle functionality under asfotase alfa. miRNA profile changes during the therapy with asfotase alfa, accompanying improvements in functionality tests and quality of life scores. [ABSTRACT FROM AUTHOR]

Idiopathic juvenile osteoporosis (IJO) is a rare condition presenting with vertebral and metaphyseal fractures that affects otherwise healthy prepubertal children. Bone mineral density (BMD) measurements are very low. The primary problem appears to be deficient bone formation, with a failure to accrue bone normally during growth. The onset in childhood suggests IJO is a genetic disorder, and a number of reports indicate that some children carry heterozygous pathogenic variants in genes known to be associated with defective osteoblast function and low bone mass, most commonly LRP5 or PLS3. However, a positive family history is unusual in IJO, suggesting the genetic background can be complex. We describe a young man with classical IJO who was investigated with a bone fragility gene panel and whole genome sequencing. The proband was found to carry four variants in three different genes potentially affecting osteoblast function. From his mother he had inherited mutations in ALPL (p.Asn417Ser) and LRP5 (p.Arg1036Gln), and from his father mutations in LRP5 (p.Asp1551Alsfs*13) and activating transcription factor 4 (ATF4) (p.Leu306Ile). His sister had also inherited the LRP5 (p.Asp1551Alsfs*13) from her father, but not the ATF4 mutation. Their spinal BMD z-scores differed substantially (sister –1.6, father –3.2) pointing to the potential importance of the ATF4 mutation. Activating transcription factor 4 acts downstream from RUNX2 and osterix and plays an important role in osteoblast differentiation and function. This case, together with others recently published, supports the view that IJO can result from clustering of mutations in genes related to osteoblast development and function. Novel genes in these pathways may be involved. Our case also emphasizes the value of detailed study of other family members. After a bone biopsy had excluded a mineralization defect due to hypophosphatasia, the proband was treated with zoledronate infusions with good clinical effect. Lay Summary: Idiopathic juvenile osteoporosis (IJO) is a rare but disabling condition presenting with vertebral and metaphyseal fractures that affects otherwise healthy prepubertal children. Bone mineral density measurements are very low. The primary problem appears to be deficient bone formation, with a failure to accrue bone normally during growth. The onset in childhood suggests IJO is a genetic disorder, but a positive family history is unusual, suggesting that its genetic basis can be complex. We describe a young man with classical IJO who was investigated with a bone fragility gene panel and whole genome sequencing. He was found to have inherited four variants in three different genes potentially affecting osteoblast function: from his mother an ALPL mutation and an LRP5 mutation, and from his father a different LRP5 mutation and a mutation in AFT4, which codes for a transcription factor important in osteoblast differentiation. Together with some recently published cases, the findings in this family indicate that IJO may have a polygenic etiology. Graphical Abstract [ABSTRACT FROM AUTHOR]

Stage IV grade C localized periodontitis (pre-puberal localized aggressive periodontitis/LPP), an extremely rare form of periodontal disease, occurs in otherwise healthy individuals (no signs of dental plaque/calculus) due a hyper-aggressive auto-immune response to high periodontopathic bacteria levels. Methods: A 4-year-old Caucasian girl with unusually high mobility of the deciduous lower left canine and localized gingival inflammation was misrecognized by multiple clinicians (initially diagnosed with hypophosphatasia, genetic and metabolic disorders, all turning negative), over a period of 4–6 months, despite initial radiographs showing clear pathognomonic signs. The LPP diagnostic was made by the last clinician, but by then the tooth was lost. Similar inflammation signs appeared around the lower deciduous right canine. X-ray examination showed similar bone and periodontal loss as previously seen, while periodontopathic bacteria tested highly positive. The patient received both mechanical cleaning and ten days of systemic antibiotic treatment (Augmentin and Metronidazole). Results: Two months later, inflammation signs disappeared, with periodontal regeneration radiologically present, and only small periodontopathic bacteria precursor concentrations. Conclusions: Despite initial periodontal loss, an adequate treatment can keep under control an LPP disease. Moreover, bone and periodontal regeneration appears if periodontopathic bacteria scores are kept lower, showing the importance of fast adequate diagnostic and treatment. [ABSTRACT FROM AUTHOR]

Mutations in dental hypophosphatasia (HPP) have been reported less than those in other types of HPP because the symptoms are mild or the dental lesions are only partial manifestations of other types of HPP. In this case, we observe the clinical manifestation of dental hypoalkaline phosphatase by analyzing the genetic mutation and biochemical parameters in child. The clinical data of the child with odonto HPP were collected and analyzed. The blood samples of the child and his parents were sequenced and verified using Sanger through a specific probe capture and high-throughput second-generation sequencing technology. Major clinical manifestations in the patient were early loss of deciduous teeth, significantly lower serum alkaline phosphatase (ALP) levels, lower active vitamin D, and increased blood phosphorus, but no abnormality was observed in the oral X-ray. Two missense mutations—c.542C>T (p. ser181leu) and c.644 T> C (p.Ile215Thr)—were found in exon 6 of the ALPL gene from the father and mother, respectively. The clinical manifestations of odonto hypophosphatasia were early loss of deciduous teeth and significantly reduced serum ALP levels. Of 2 mutations—c.542C>T (p.ser181leu) and c.644 T> C (p.Ile215Thr)—in the ALPL gene, c.644 T> C (p.Ile215Thr) was a new mutation. [ABSTRACT FROM AUTHOR]

Background: A balanced diet rich in calcium and protein is recommended for bone-healthy people and osteoporosis patients, but it may also be important for rare bone disease (RBD). Little data is available on RBD and diet. Therefore, the aim of this study was to evaluate the nutritional behavior of patients with RBD. Methods: This single-center, cross-sectional, questionnaire-based study assessed the nutritional behavior of RBD patients (X-linked hypophosphatemia (XLH), osteogenesis imperfecta (OI), hypophosphatasia (HPP)), osteoporosis (OPO) patients and healthy controls (CTRL). The nutritional questionnaire comprised 25 questions from seven nutritional areas. The associations between socioeconomic factors and BMI were assessed by age-adjusted univariate analysis of covariance (ANCOVA). Results: Fifty patients with RBD (17 OI, 17 HPP, 16 XLH; mean age of 48.8 ± 15.9, 26.0% male, mean BMI 26.2 ± 5.6), 51 with OPO (mean age 66.6 ± 10.0, 9.8% male, mean BMI 24.2 ± 3.9) and 52 CTRL (mean age 50.8 ± 16.3, 26.9% male, mean BMI 26.4 ± 4.7) participated. Twenty-six (52.0%) RBD, 17 (33.4%) OPO and 24 (46.1%) CTRL were overweight or obese according to BMI. Only a minority of RBD, OPO and CTRL had a daily intake of at least three portions of milk or milk products (17.3% RBD, 15.6% OPO, 11.6% CTRL, p = 0.453). In general, similar nutritional behavior was observed between the three subgroups. However, significant differences were found in caffeine consumption (p = 0.016), fruit/vegetable juice consumption (p = 0.034), portions of fish per week (p = 0.044), high-fat meals per week (p = 0.015) and consumption of salty snacks (p = 0.001). Conclusion: Nutritional counseling, controlling BMI and ensuring sufficient calcium and protein intake are crucial in patients with osteoporosis as well as in rare bone diseases. Vitamin D does not appear to be sufficiently supplied by the diet, and therefore supplementation should be considered in patients with bone diseases. [ABSTRACT FROM AUTHOR]

Abstract Background Early-onset bone dysplasia is a common manifestation of hypophosphatasia (HPP), an autosomal inherited disease caused by ALPL mutation. ALPL ablation induces prototypical premature bone ageing characteristics, resulting in impaired osteogenic differentiation capacity of human bone marrow mesenchymal stem cells (hBMMSCs). As angiogenesis is tightly coupled with osteogenesis, it also plays a necessary role in sustaining bone homeostasis. We have previously observed a decrease in expression of angiogenesis marker gene CD31 in the metaphysis of long bone in Alpl +/− mice. However, the role of ALPL in regulation of angiogenesis in bone has remained largely unknown. Methods Exosomes derived from Normal and HPP hBMMSCs were isolated and identified by ultracentrifugation, transmission electron microscopy, and nanoparticle size measurement. The effects of ALPL on the angiogenic capacity of hBMMSCs from HPP patients were assessed by immunofluorescence, tube formation, wound healing and migration assay. exo-ELISA and Western Blot were used to evaluate the exosomes secretion of hBMMSCs from HPP, and the protein expression of VEGF, PDGFBB, Angiostatin and Endostatin in exosomes respectively. Results We verified that ALPL ablation resulted in impaired pro-angiogenic capacity of hBMMSCs, accounting for reduced migration and tube formation of human umbilical vein endothelial cells, as the quantities and proteins composition of exosomes varied with ALPL expression. Mechanistically, loss of function of ALPL enhanced ATP release. Additional ATP, in turn, led to markedly elevated level of ATP receptor P2X7, which consequently promoted exosomes secretion, resulting in a decreased capacity to promote angiogenesis. Conversely, inhibition of P2X7 increased the angiogenic induction capacity by preventing excessive release of anti-angiogenic exosomes in ALPL deficient-hBMMSCs. Conclusion The ALPL–ATP axis regulates the pro-angiogenic ability of hBMMSCs by controlling exosomes secretion through the P2X7 receptor. Thus, P2X7 may be proved as an effective therapeutic target for accelerating neovascularization in ALPL–deficient bone defects.

Malignant infantile osteopetrosis is a rare inherited disease of bone metabolism, in which osteoclast dysfunction and diminished bone turnover lead to diffuse sclerosis with obliteration of the medullary cavities and narrowing of the skull base neural foramina. We report a case of malignant infantile osteopetrosis with bone marrow failure and optic atrophy that co-occurred with hypophosphatasia, another rare inherited bone disease, in a 6-year-old boy. Key imaging signs of these rare diseases are discussed.

Hypophosphatasia is a rare genetic disease characterized by abnormal alkaline phosphatase activity and deficiency of bone and teeth mineralization. Hypophosphatasia is well known in pediatrics with typical presentations in children, but mild forms can also be present in adults and are difficult to detect. We present the case of a 50-year-old woman referred for pain management, with a previous diagnosis of fibromyalgia. The association of clinical features (diffuse pain syndrome, early dental loosening, personal history of two fractures with osteoporosis, and family history of osteoporosis) with radiographic (heterotopic calcifications of the yellow and interspinous lumbar ligaments) and biological (low levels of total alkaline phosphatase) indices was suggestive of hypophosphatasia, which was confirmed by genetic analysis. We review and discuss the association between hypophosphatasia, musculoskeletal pain, and calcium pyrophosphate deposition and the importance of raising the diagnosis of adult-onset hypophosphatasia when facing these two rheumatologic entities. [ABSTRACT FROM AUTHOR]

Most serum alkaline phosphatase (ALP) (> 90 %) originates from the liver and bone. Normally, the contribution from other tissues, such as the intestine or kidney, is much smaller, although the placenta is an important source during pregnancy. Elevated ALP levels are usually indicative of liver or bone disease. The analysis of other liver enzymes, particularly GGT--which is elevated in liver damage and normal in bone diseases--usually clarifies the origin. When in doubt, the bone isoform can be measured, or a profile of all isoenzymes can be conducted. [ABSTRACT FROM AUTHOR]

Hypophosphatasia is a rare inherited metabolic disorder caused by the deficiency of tissue-nonspecific alkaline phosphatase. More severe and early onset cases present symptoms of muscle weakness, diminished motor coordination, and epileptic seizures. These neurological manifestations are poorly characterized. Thus, it is urgent to discover novel differentially expressed genes for investigating the genetic mechanisms underlying the neurological manifestations of hypophosphatasia. RNA-sequencing data offer a high-resolution and highly accurate transcript profile. In this study, we apply an empirical Bayes model to RNA-sequencing data acquired from the spinal cord and neocortex tissues of a mouse model, individually, to more accurately estimate the genetic effects without bias. More importantly, we further develop two integration methods, weighted gene approach and weighted Z method, to incorporate two RNA-sequencing data into a model for enhancing the effects of genetic markers in the diagnostics of hypophosphatasia disease. The simulation and real data analysis have demonstrated the effectiveness of our proposed integration methods, which can maximize genetic signals identified from the spinal cord and neocortex tissues, minimize the prediction error, and largely improve the prediction accuracy in risk prediction. [ABSTRACT FROM AUTHOR]

(1) Background: The use of complementary and alternative medicine (CAM) has seen a notable increase in popularity. However, there is an absence of data regarding the prevalence of CAM use in patients with rare bone diseases (RBDs). (2) Methods: This monocentric, cross-sectional study was carried out in a reference hospital for RBDs. RBD patients included individuals with osteogenesis imperfecta, hypophosphatasia and X-linked hypophosphatemia, and their data were compared with those of patients with osteoporosis (OPO) and of healthy controls (CON). This study utilized the German version (I-CAM-G) of the I-CAM questionnaire. (3) Results: This study comprised 50 RBD patients [mean age (SD) of 48.8 (±15.9), 26% male], 51 OPO patients [66.6 (±10.0), 9.8% male] and 52 controls [50.8 (±16.3), 26.9% male]. Treatments by naturopaths/healers were more prevalent in the RBD group (11.4%) compared with OPO (0%) and CON (5.8%) (p = 0.06). More than half of the OPO (60.8%) and CON (63.5%) patients and 46% of the RBD patients reported vitamin/mineral intake within the past 12 months (p = 0.16). Individuals with tertiary education had a significantly higher odds ratio of 2.64 (95% CI: 1.04–6.70, p = 0.04) for visiting any CAM provider. Further, OPO patients were significantly less likely to use self-help techniques compared with the CON group (OR = 0.42, 95% CI: 0.19–0.95; p = 0.04). (4) Conclusions: Herbal medicine, vitamin and mineral supplements, and self-help techniques were the most common forms of CAM reported by patients with RBDs. However, the use of CAM was generally low. [ABSTRACT FROM AUTHOR]

Background: Hypophosphatasia (HPP) is a rare inherited disease caused by deficient activity of tissue-nonspecific alkaline phosphatase. Many adults with HPP have a high burden of disease, experiencing chronic pain, fatigue, limited mobility, and dental issues, contributing to decreased health-related quality of life (HRQoL). HPP may be treated with the enzyme replacement therapy asfotase alfa though real-world data in adults are limited. This analysis was conducted to assess the clinical effectiveness of asfotase alfa among adults in the Global HPP Registry. Methods: The Global HPP Registry is an observational, prospective, multinational study. Adults ≥ 18 years of age were included in this analysis if they had serum alkaline phosphatase (ALP) activity below the age- and sex-adjusted reference ranges, and/or ALPL variant(s), and received asfotase alfa for ≥ 6 months. Mobility was assessed with the 6-Minute Walk Test (6MWT), and patient-reported outcomes tools were used to assess pain (Brief Pain Inventory-Short Form), quality of life (36-item Short Form Health Survey, version 2 [SF-36v2]), and disability (Health Assessment Questionnaire-Disability Index) at multiple time points from baseline through Month 36. Data were collected as per usual standard of care; patients may not have contributed data at all time points. Results: A total of 190 patients met the inclusion criteria. For patients with ≥ 1 follow-up measurement, the mean distance achieved on 6MWT increased from 404 m (range 60–632 m) at baseline (n = 31) to 484 m at Month 12 (range 240–739 m; n = 18) and remained above baseline through Month 36 (n = 7). Improvements in mean self-reported pain severity scores ranged from − 0.72 (95% CI: − 1.23, − 0.21; n = 38) to − 1.13 (95% CI: − 1.76, − 0.51; n = 26) and were observed at all time points. Improvements in the Physical Component Summary score of SF-36v2 were achieved by Month 6 and sustained throughout follow-up. There was a trend toward improvement in the Mental Component Summary score of SF-36v2 at most time points, with considerable fluctuations from Months 12 (n = 28) through 36 (n = 21). The most frequent adverse events were injection site reactions. Conclusions: Adults with HPP who received asfotase alfa for ≥ 6 months experienced improvements in mobility, physical function, and HRQoL, which were maintained over 3 years of follow-up. Registration: NCT02306720; EUPAS13514. [ABSTRACT FROM AUTHOR]

Hypophosphatasia (HPP) is a rare genetic condition associated with poor bone mineralization, low serum alkaline phosphatase, high urinary pyrophosphate excretion, and nephrocalcinosis. Nephrocalcinosis is thought to develop due to the increased filtered loads associated with hypercalcemia and hyperphosphatemia, but the composition of these calcifications is incompletely understood. We report the first ever magnesium pyrophosphate (MgPPi) urinary stone, which prompted the new diagnosis of HPP in a 12-year-old boy. Stone analysis labs should include infrared spectra of PPi salts in their reference libraries to facilitate identification of these rare but clinically important stones.

Background/Objective: Hypophosphatasia (HPP) is a rare disease associated with low serum alkaline phosphatase (ALP) activity. Here, we present a case of a patient with normal serum ALP levels diagnosed with HPP. Case Report: A 36-year-old woman presented with progressive fatigue, weakness, and joint pain. She had been evaluated in the past for genetic disorders due to these symptoms and was found to have a history of several total ALP levels within normal limits but elevated vitamin B6 levels. She also reported having loose teeth and “gray gums” during her childhood. Bone-specific ALP was tested for suspicion of HPP and returned at 4.4 μ/L (reference range, 5.3-19.5 μg/L), which prompted genetic testing. Genetic testing confirmed a positive pathogenetic variant of the ALPL gene, the c.542C>T (p.Ser181Leu) variant. She started asfotase alfa treatment to improve her symptoms. Discussion: HPP was diagnosed based on clinical suspicion supported by laboratory findings, which can cause it to be underdiagnosed or misdiagnosed. Current literature reports that a low total ALP level is the main biochemical marker of HPP and the only level needed to diagnose the disease. However, bone-specific ALP, a common marker used for bone turnover, has not been required to be tested. Conclusion: This case highlights a patient with normal total ALP, but low bone-specific ALP diagnosed with HPP confirmed by genetic testing. This case warrants future investigation into the diagnostic approach to HPP and the diagnostic utility between ALP and bone-specific ALP.

Hypophosphatasia (HPP) is a rare condition characterized by abnormal bone mineralization. The manifestations of HPP vary from no symptoms to intrauterine fetal death; short stature is another indication of HPP. A 3 ½-year-old boy presented with short stature, transient hypercalcemia, and mild gait disturbance without definite bony deformity. Laboratory examination revealed transient hypercalcemia, normal phosphorous and 25-hydroxy vitamin D levels, and mildly low alkaline phosphatase levels. A targeted next-generation sequencing panel associated with inborn errors of metabolism revealed a pathogenic heterozygous mutation in the ALPL gene, c.979T>C (p.Phe327Leu). When a child visits a hospital with short stature, decreased height velocity, and low alkaline phosphatase level, clinicians should consider the possibility of HPP even if definite skeletal dysplasia is not evident.

Introduction: Hypophosphatasia (HPP) is an inborn metabolic error caused by mutations in the ALPL gene encoding tissue non-specific alkaline phosphatase (TNSALP) and leading to decreased alkaline phosphatase (ALP) activity. Although the main characteristic of this disease is bone involvement, it presents a great genetic and clinical variability, which makes it a systemic disease. Methods: Patients were recruited based on biochemical assessments. Diagnosis was made by measuring serum ALP and pyridoxal 5-phosphate levels and finally by Sanger sequencing of the ALPL gene from peripheral blood mononuclear cells. Characterization of the new variants was performed by transfection of the variants into HEK293T cells, where ALP activity and cellular localization were measured by flow cytometry. The dominant negative effect was analyzed by co-transfection of each variant with the wild-type gene, measuring ALP activity and analyzing cellular localization by flow cytometry. Results: Two previously undescribed variants were found in the ALPL gene: leucine 6 to serine missense mutation (c.17T>C, L6S) affecting the signal peptide and threonine 167 deletion (c.498_500delCAC, T167del) affecting the vicinity of the active site. These mutations lead mainly to nonpathognomonic symptoms of HPP. Structural prediction and modeling tools indicated the affected residues as critical residues with important roles in protein structure and function. In vitro results demonstrated low TNSALP activity and a dominant negative effect in both mutations. The results of the characterization of these variants suggest that the pleiotropic role of TNSALP could be involved in the systemic effects observed in these patients highlighting digestive and autoimmune disorders associated with TNSALP dysfunction. Conclusions: The two new mutations have been classified as pathogenic. At the clinical level, this study suggests that both mutations not only lead to pathognomonic symptoms of the disease, but may also play a role at the systemic level. [ABSTRACT FROM AUTHOR]

Background and Objectives: Stage IV grade C localized periodontitis (pre-puberal localized aggressive periodontitis/LPP) is a rare form of inflammatory periodontal disease occurring in clinically healthy individuals (no/small calculus/dental plaque traces), due a hyper-aggressive auto-immune response to high amounts of bacteria present in the oral cavity. Case Presentation: This case report describes a 4-year-old Caucasian girl with localized gingival inflammation and advanced bone loss around the temporary lower left canine. The first diagnostic assumption was hypophosphatasia, and the patient was sent for further genetic and metabolic investigations (which turned out to be negative). The LPP diagnosis was made during the family's summer holidays due to her parents' concerns about persistent gingival inflammation and tooth mobility. Results: The diagnosis of LPP was supported by clinical oral examination results, earlier X-rays, earlier blood tests, and a periodontal bacterial test. The treatment was limited to avoid spreading inflammation to other teeth (via topical antibiotic treatment) due to our limited time frame, while the main problem of excessive amounts of periodontal bacteria in the oral cavity was not addressed. The tooth was eventually lost. Conclusions: The ability to early recognize radiological and clinical LPP signs correlated with understanding of its pathological auto-immune mechanism is extremely important for expanding treatment options, since bone preservation and reducing amounts of bacteria are strictly correlated with therapeutic speed. [ABSTRACT FROM AUTHOR]

Context Impairments in musculoskeletal and mental health are common in adults with Hypophosphatasia (HPP). Restricted phosphorus intake has been suggested to positively affect symptoms in HPP, but there is a lack of interventional evidence. Objective This work aimed to evaluate the effect of a phosphorus-restricted, calcium-adjusted diet on musculoskeletal and mental health in HPP. Methods A prospective, noncontrolled, single-center interventional study (NuSTEPS II) was conducted among outpatients at the Osteology Department, University of Wuerzburg, Germany. A total of 26 adults with an established HPP diagnosis received a standardized diet with a defined daily intake of phosphorus (1160-1240 mg/d) and calcium (870-930 mg/d) over 8 weeks. Main outcome measures were functional testing and patient-reported outcome measures. Results At 8 weeks, significant improvements were observed in usual gait speed (P =.028) and the chair-rise test (P =.019), while no significant changes were seen in the 6-minute walk test (P =.468) and the timed up-and-go test (P =.230). Pain was not significantly reduced according to the visual analog scale (VAS) (P =.061), pain subscale of the 36-Item Short-Form Health Survey (SF-36) (P =.346), and Pain Disability Index (P =.686). Further, there was a significant improvement in the SF-36 vitality subscale (P =.022) while all other subscales as well as the Lower Extremity Functional Scale (P =.670) and the Fatigue Assessment Scale (P =.392) did not change significantly. Adjustments of mineral intake were not associated with relevant alterations regarding the intake of energy and energy-supplying nutrients or body composition. Conclusion Adjusting phosphorus and calcium intake may positively affect individual symptoms in adults with HPP, but overall clinical effectiveness regarding major issues like pain and endurance appears limited. [ABSTRACT FROM AUTHOR]

Hypophosphatasia (HPP) is an inherited disease caused by variants of the ALPL gene encoding tissue‐nonspecific alkaline phosphatase. Adult‐onset HPP (adult HPP), known as a mild form of HPP, develops symptoms involving osteomalacia after the age of 18 years. Asfotase alfa (AA) is a modulated recombinant human alkaline phosphatase (ALP) that has been established as a first‐line therapy for severe forms of HPP, such as perinatal and infantile forms. We described a 64‐year‐old female who presented with pseudofractures in bilateral femur diaphyses and impaired mobility. Low serum ALP activity and a high concentration of urine phosphoethanolamine indicated the diagnosis of HPP, which was confirmed by the identification of a homozygous variant in the ALPL gene (c.319G > A; p.Val107Ile). An in vitro transfection experiment to measure the ALP activity of this novel variant protein was performed, resulting in 40% of the residual enzymatic activity compared with the wild type. AA was initiated to facilitate the union of pseudofracture and to improve mobility. After 6 months, radiographic images revealed the disappearance of fracture lines, and improvement of ambulatory ability was confirmed by the 6‐minute walk test (525 to 606 m). The EQ‐5D‐5L index was also improved (0.757 to 0.895). Within a follow‐up period, the levels of urine pyrophosphate corrected by urine creatinine (uPPi/Cre) declined in parallel with the level of plasma PPi (plasma PPi: 6.34 to 1.04 μM, uPPi/Cre: 226.8 to 75.4 nmol/mg). The beneficial effect of AA on pseudofracture healing in adult HPP was presented, although the application of AA should be restricted to patients exhibiting relatively severe manifestations. In addition, a novel pathogenic variant of the ALPL gene was identified with the supportive result of functional analysis. Furthermore, when monitoring patients with HPP treated with AA, uPPi/Cre might be a convenient substitute for plasma PPi, which requires immediate filtration after blood sampling. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Urolithiasis composed of pyrophosphate salts has only been reported in animals, in the form of potassium magnesium pyrophosphate. However, there have been no reports of pyrophosphate stones in humans. Hypophosphatasia is an inherited disease characterized by low alkaline phosphatase activity and elevated levels of pyrophosphate in blood and urine. Urolithiasis is a part of the hypophosphatasia phenotype. The role of elevated urine pyrophosphate levels in the formation of stones in hypophosphatasia is unknown. Here, we report a case of a 60-year-old man with recurrent urolithiasis. The patient’s most recent presentation was gross hematuria and his computed tomography scan showed bilateral kidney stones. Stones were removed via retrograde intrarenal surgery. Stone analysis revealed a composition of potassium magnesium pyrophosphate. The patient also has a long history of fracturing bone disease which led to the consideration of hypophosphatasia as the cause of both his bone disease and pyrophosphate stones. Hypophosphatasia was confirmed by genetic analysis. Pyrophosphate has been of interest in the fields of mineral metabolism because of its action as a crystallization inhibitor. However, pyrophosphate at elevated concentrations in the presence of divalent cations can exceed its solubility. Nephrocalcinosis and stone disease have been described in hypophosphatasia; stones have been assumed to be calcium phosphate but no compositional analysis has been reported. This is the first report of human stones composed of pyrophosphate salts, which led to the subsequent diagnosis of hypophosphatasia in this patient.

Background: A balanced diet rich in calcium and protein is recommended for bone-healthy people and osteoporosis patients, but it may also be important for rare bone disease (RBD). Little data is available on RBD and diet. Therefore, the aim of this study was to evaluate the nutritional behavior of patients with RBD. Methods: This single-center, cross-sectional, questionnaire-based study assessed the nutritional behavior of RBD patients (X-linked hypophosphatemia (XLH), osteogenesis imperfecta (OI), hypophosphatasia (HPP)), osteoporosis (OPO) patients and healthy controls (CTRL). The nutritional questionnaire comprised 25 questions from seven nutritional areas. The associations between socioeconomic factors and BMI were assessed by age-adjusted univariate analysis of covariance (ANCOVA). Results: Fifty patients with RBD (17 OI, 17 HPP, 16 XLH; mean age of 48.8 ± 15.9, 26.0% male, mean BMI 26.2 ± 5.6), 51 with OPO (mean age 66.6 ± 10.0, 9.8% male, mean BMI 24.2 ± 3.9) and 52 CTRL (mean age 50.8 ± 16.3, 26.9% male, mean BMI 26.4 ± 4.7) participated. Twenty-six (52.0%) RBD, 17 (33.4%) OPO and 24 (46.1%) CTRL were overweight or obese according to BMI. Only a minority of RBD, OPO and CTRL had a daily intake of at least three portions of milk or milk products (17.3% RBD, 15.6% OPO, 11.6% CTRL, p = 0.453). In general, similar nutritional behavior was observed between the three subgroups. However, significant differences were found in caffeine consumption (p = 0.016), fruit/vegetable juice consumption (p = 0.034), portions of fish per week (p = 0.044), high-fat meals per week (p = 0.015) and consumption of salty snacks (p = 0.001). Conclusion: Nutritional counseling, controlling BMI and ensuring sufficient calcium and protein intake are crucial in patients with osteoporosis as well as in rare bone diseases. Vitamin D does not appear to be sufficiently supplied by the diet, and therefore supplementation should be considered in patients with bone diseases.

Hypophosphatasia is rare genetic disease caused by tissue-nonspecific alkaline phosphatase deficiency due to the mutation in the ALPL gene. Disease can manifest in utero, in childhood or in adults depending on its form and severity. This article presents modern data on the epidemiology, etiology, and clinical signs of hypophosphatasia in children, covers in details differential diagnostic search, and gives guidelines for its evidence-based treatment. Without timely treatment the prognosis of the disease is unfavorable in most cases. Such patients require follow-up by multidisciplinary team of physicians. The only effective method of treatment is enzyme replacement therapy with asfotase alfa. Symptomatic therapy is also crucial as well as physiotherapeutic procedures and therapeutic exercise programs (at rehabilitation stage).

IntroductionHypophosphatasia (HPP) is an inborn metabolic error caused by mutations in the ALPL gene encoding tissue non-specific alkaline phosphatase (TNSALP) and leading to decreased alkaline phosphatase (ALP) activity. Although the main characteristic of this disease is bone involvement, it presents a great genetic and clinical variability, which makes it a systemic disease.MethodsPatients were recruited based on biochemical assessments. Diagnosis was made by measuring serum ALP and pyridoxal 5-phosphate levels and finally by Sanger sequencing of the ALPL gene from peripheral blood mononuclear cells. Characterization of the new variants was performed by transfection of the variants into HEK293T cells, where ALP activity and cellular localization were measured by flow cytometry. The dominant negative effect was analyzed by co-transfection of each variant with the wild-type gene, measuring ALP activity and analyzing cellular localization by flow cytometry.ResultsTwo previously undescribed variants were found in the ALPL gene: leucine 6 to serine missense mutation (c.17T>C, L6S) affecting the signal peptide and threonine 167 deletion (c.498_500delCAC, T167del) affecting the vicinity of the active site. These mutations lead mainly to non-pathognomonic symptoms of HPP. Structural prediction and modeling tools indicated the affected residues as critical residues with important roles in protein structure and function. In vitro results demonstrated low TNSALP activity and a dominant negative effect in both mutations. The results of the characterization of these variants suggest that the pleiotropic role of TNSALP could be involved in the systemic effects observed in these patients highlighting digestive and autoimmune disorders associated with TNSALP dysfunction.ConclusionsThe two new mutations have been classified as pathogenic. At the clinical level, this study suggests that both mutations not only lead to pathognomonic symptoms of the disease, but may also play a role at the systemic level.

Currently, no published cases report concomitant X-linked hypophosphatemia (XLH) and adult hypophosphatasia (HPP). Both diseases share clinical phenotypes that are almost indistinguishable. The correct diagnosis may be missed without a standardized laboratory and genetic testing approach. Pathogenic variants in the phosphate regulating endopeptidases homolog X-linked gene (PHEX) and the tissue-nonspecific alkaline phosphatase gene (ALPL) are genes that cause XLH and HPP, respectively. We describe a concomitant yet undescribed genetic pathogenic variant in a family. A 61-year-old woman was referred by orthopedic surgery for the presence of bilateral leg bowing and short stature during the assessment of knee surgery. The patient had a biochemical workup relevant for low serum phosphorus and 1,25-dihydroxy vitamin D and normal alkaline phosphatase (ALP). Genetic analysis revealed pathogenic variants in PHEX and ALPL. Her 42-year-old daughter shared identical symptoms and genetic variants with her mother. Both patients started conventional treatment for XLH with phosphorus and vitamin D, and the daughter later switched to burosumab-twza. Adult XLH and HPP may have similarities in clinical presentation but differ in some essential laboratory findings. Normal ALP levels helped direct our diagnosis toward XLH. However, the diagnosis was challenging due to the presence of concurrent variants in the genes involved. These variants illustrate the significant heterogeneity of the clinical expression. [ABSTRACT FROM AUTHOR]