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Hypophosphatasia (HPP) is a rare, inherited metabolic disease caused by deficient activity of tissue-nonspecific alkaline phosphatase (TNSALP). Efzimfotase alfa (ALXN1850) is a second-generation TNSALP enzyme replacement therapy in development for HPP. This first-in-human open-label, dose-escalating phase 1 trial evaluated safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of efzimfotase alfa. Fifteen adults (five per cohort) with HPP received efzimfotase alfa 15 mg (cohort 1), 45 mg (cohort 2), or 90 mg (cohort 3) as one i.v. dose followed by 3 weekly s.c. doses. The primary objective was to assess safety and tolerability. Secondary objectives included pharmacokinetics, pharmacodynamics of ALP substrates known to be biomarkers of disease (inorganic pyrophosphate [PPi] and pyridoxal 5'-phosphate [PLP]), and immunogenicity. Treatment-emergent adverse events (TEAEs) occurred in 12 (80%) participants. Eight (53%) participants had injection site reactions (ISRs), observed after 10 of 41 (24%) s.c. injections. Most ISR TEAEs were mild and resolved within 1-2 days. Peak and total exposures of efzimfotase alfa increased in a greater than dose-proportional manner over 15-90 mg after i.v. and s.c. dosing. Arithmetic mean elimination t½ was approximately 6 days; absolute bioavailability ranged from 28.6% to 36.8% over the s.c. dose range of 15-90 mg. Dose-dependent reductions in plasma concentrations of PPi and PLP relative to baseline reached nadir in the first week after i.v. dosing and were sustained for 3-4 weeks after the last s.c. dose. Four (27%) participants tested positive for antidrug antibodies (ADAs), three of whom were ADA positive before the first dose of efzimfotase alfa. ADAs had no apparent effect on efzimfotase alfa pharmacokinetics/pharmacodynamics. No participants were positive for neutralizing antibodies. Efzimfotase alfa demonstrated acceptable safety, tolerability, and pharmacokinetic profiles and was associated with sustained reductions in biomarkers of disease in adults with HPP, supporting further evaluation in adult and pediatric patients. REGISTRATION: NCT04980248.
Hypophosphatasia (HPP) is a rare metabolic disease caused by low activity of tissue non-specific alkaline phosphatase (TNSALP), which is an enzyme involved in the formation and healing of bone and function of other body systems. People with HPP experience fractures, difficulty moving and walking, muscle weakness, pain, fatigue (tiredness), and teeth problems. Babies with HPP often have life-threatening breathing problems, craniosynostosis (early closure of skull bones), seizures that respond to treatment with vitamin B6, failure to thrive (inability to gain weight), and weak and abnormally shaped bones. Enzyme replacement therapy (ERT) for HPP was developed to supplement defective TNSALP with active enzyme, thus improving bone health and the symptoms of HPP. Asfotase alfa, the first ERT approved for the treatment of HPP is given by subcutaneous injection either 3 or 6 times per week. Efzimfotase alfa is a second-generation ERT that is being developed for the treatment of HPP. While similar to asfotase alfa, efzimfotase alfa has incorporated several changes that have the potential to require lower doses and reduce injection volume and dosing frequency, thereby potentially improving the treatment experience for patients. This first-in-human study investigated the safety, tolerability, pharmacokinetics (how a drug is absorbed into, distributed throughout, and removed from the body), pharmacodynamics (effects of the drug within the body), and immunogenicity (ability of a drug to provoke an undesirable immune response) of four injections of efzimfotase alfa when given by intravenous and subcutaneous routes of administration to adults with HPP. Our results showed that efzimfotase alfa has acceptable safety and pharmacokinetics and is effective for reducing biomarkers (measurable substances that reflect underlying disease) when given once weekly by subcutaneous injection, supporting further evaluation of efzimfotase alfa in planned clinical trials in adult and pediatric patients with HPP.
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Hypophosphatasia (HPP) is a rare, inherited metabolic disorder caused by deficient tissue-nonspecific alkaline phosphatase activity. This study assessed the impact of treatment with asfotase alfa on patient-reported outcomes (PROs) in adults with pediatric-onset HPP. A longitudinal, telephone-based survey was administered to eligible individuals enrolled in a patient support program. Interviews were conducted at study entry (prior to asfotase alfa initiation) and after 3, 6, and 12 mo. PROs-Patient Health Questionnaire-9 [PHQ-9], Work Productivity and Activity Impairment Questionnaire: Specific Health Problem [WPAI:SHP], Patient-Reported Outcomes Measurement Information System 29 [PROMIS-29], and Routine Assessment of Patient Index Data 3 [RAPID3]-were assessed at each time point. Appropriate statistical tests were performed to assess score changes. Among 50 enrolled patients (mean age: 46 yr [SD: 15.4]; 80% female; 94% White), 49 were evaluable at 3 mo, 44 at 6 mo, and 29 at 12 mo. By month 3, statistically significant improvements from baseline were detected in PHQ-9 scores (10.6 vs 5.8 [P < .0001]), PROMIS-29 domain scores (overall physical function: 38.0 vs 43.0 [P = .001]; anxiety: 57.5 vs 51.5 [P = .0011]; fatigue: 63.3 vs 55.3 [P < .0001]; sleep disturbances: 58.8 vs 54.3 [P = .0099]; ability to participate in social roles and activities: 42.6 vs 47.7 [P = .0012]; and pain interference: 63.8 vs 58.4 [P = .001]), and RAPID3 domain scores (functional status: 2.7 vs 1.1 [P < .0001]; pain tolerance: 6.0 vs 3.2 [P < .0001]; and global health estimate: 5.1 vs 2.7 [P < .0001]). Improvements persisted at month 12. Patients also showed improvements in WPAI:SHP domain scores at month 6 (presenteeism: 39.6% vs 14.1% [P < .0001] and work productivity loss: 41.9% vs 14.1% [P < .0001]). Treatment with asfotase alfa was associated with improved quality of life across several domains.
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Osteogenesis imperfecta (OI) is a rare genetic disorder commonly caused by variants of the type I collagen genes COL1A1 and COL1A2. OI is associated with increased bone fragility, bone deformities, bone pain, and reduced growth. Setrusumab, a neutralizing antibody to sclerostin, increased areal bone mineral density (aBMD) in a 21-week phase 2a dose escalation study. The phase 2b Asteroid (NCT03118570) study evaluated the efficacy and safety of setrusumab in adults. Adults with a clinical diagnosis of OI type I, III, or IV, a pathogenic variant in COL1A1/A2, and a recent fragility fracture were randomized 1:1:1:1 to receive 2, 8, or 20 mg/kg setrusumab doses or placebo by monthly intravenous infusion during a 12-month treatment period. Participants initially randomized to the placebo group were subsequently reassigned to receive setrusumab 20 mg/kg open label. Therefore, only results from the 2, 8, and 20 mg/kg double-blind groups are presented herein. The primary endpoint of Asteroid was change in distal radial trabecular vBMD from baseline at Month 12, supported by changes in high-resolution peripheral quantitative computed tomography micro finite element-derived bone strength. A total of 110 adults were enrolled with similar baseline characteristics across treatment groups. At 12 months, there was a significant increase in mean (SE) failure load in the 20 mg/kg group (3.17% [1.26%]) and stiffness in the 8 (3.06% [1.70%]) and 20 mg/kg (3.19% [1.29%]) groups from baseline. There were no changes in radial trabecula vBMD (p > 0.05). Gains in failure load and stiffness were similar across OI types. There were no significant differences in annualized fracture rates between doses. Two adults in the 20 mg/kg group experienced related serious adverse reactions. Asteroid demonstrated a beneficial effect of setrusumab on estimates of bone strength across the different types of OI and provides the basis for additional phase 3 evaluation.
Osteogenesis imperfecta, or OI, is a rare disorder affecting patients' bones causing pain and an increased chance of the bone breaking. Setrusumab is a possible treatment for OI being studied in a clinical trial called Asteroid. The goal of Asteroid was to determine which dose of setrusumab helped adults with OI the most: 2, 8, or 20 mg/kg. Researchers looked at the density of patients' bones and estimated how strong their bones were before setrusumab and again after 12 months of treatment to see how they improved with treatment. Researchers could compare these improvements to see which dose of setrusumab helped patients the most. Patients on the highest dose of setrusumab (20 mg/kg) experienced improvements in the density of their arm bones (radius) and leg bones (tibia) after 12 months. The strength of these bones also improved. The density of other bones including the spine, hip, and the overall skeleton (total body) also improved with treatment. Of patients who had side effects after receiving setrusumab, most were mild or moderate intensity. Overall, setrusumab improved the bones of patients with OI with no serious safety concerns. More studies will include even more patients to see how setrusumab can improve their bones.
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CONTEXT: Tumor-induced osteomalacia (TIO) is an ultra-rare, paraneoplastic syndrome caused by tumors that secrete fibroblast growth factor 23 (FGF23). Initial signs and musculoskeletal symptoms can be non-specific and unrecognized, leading to long delays in diagnosis and treatment, which results in severe and progressive disability in patients with TIO. This review aimed to identify published evidence on healthcare resource use in TIO to better understand the burden of the disease. EVIDENCE ACQUISITION: A targeted literature review was conducted to identify publications reporting on disease characteristics and healthcare resource use associated with TIO. EVIDENCE SYNTHESIS: In total, 414 publications were included in the review, of which 376 were case reports. From the case reports, data on 621 patients were extracted. These patients had a mean (standard deviation) age of 46.3 (15.8) years; 57.6% were male. Mean time from first symptoms to diagnosis of TIO was 4.6 (4.7) years and, in cases where imaging tests were reported, patients underwent a mean of 4.1 (2.7) procedures. Tumor resection was attempted in 81.0% of patients and successful in 67.0%. Fracture was reported in 49.3% of patients. Results from association analyses demonstrated that longer time to diagnosis was associated with poorer tumor resection outcomes and a higher probability of tumor recurrence. Unfavorable tumor resection outcomes were associated with greater use of pharmacologic treatment and a greater likelihood of orthopedic surgery. CONCLUSION: TIO is associated with a substantial healthcare resource burden. Improvements in the diagnostic process could lead to better management of TIO, thereby benefiting patients and reducing that burden.
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Hypophosphatasia (HPP) is a rare, inherited metabolic disease characterized by low tissue-nonspecific alkaline phosphatase activity due to ALPL gene variants. We describe ALPL variants from the observational, prospective, multinational Global HPP Registry. Inclusion in the analysis required a diagnosis of HPP, low serum ALP activity, and ≥1 ALPL variant. Of 1176 patients enrolled as of September 2022, 814 met inclusion criteria in Europe (48.9%), North America (36.7%), Japan (10.2%), Australia (2.6%), and elsewhere (1.6%). Most patients (74.7%) had 1 ALPL variant; 25.3% had ≥2 variants. Nearly all patients (95.6%) had known disease-causing variants; 4.4% had variants of uncertain significance. Disease-causing variants were predominantly missense (770/1556 alleles). The most common variants were c.571G>A (102/1628 alleles), c.1250A>G (66/1628 alleles), and c.1559del (61/1628 alleles). Variant profiles were generally consistent, except in Japan, where a higher proportion of patients (68.7%) had ≥2 ALPL variants, likely because more had disease onset before age 6 months (53.0% vs. 10.1%-23.1% elsewhere). Frameshift mutations (61/164 alleles) and inframe deletions (7/164 alleles) were more common in Japan. Twenty-three novel variants were discovered, each in a single geographic region, predominantly Europe. Analyses confirmed previously known ALPL variants, identified novel variants, and characterized geographic variation in frequency and type of ALPL variants in a large population.
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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.
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Dor Crônica , Hipofosfatasia , Imunoglobulina G , Proteínas Recombinantes de Fusão , Adulto , Humanos , Fosfatase Alcalina/uso terapêutico , Hipofosfatasia/tratamento farmacológico , Qualidade de Vida , Estudos Prospectivos , Sistema de Registros , Terapia de Reposição de Enzimas/métodosRESUMO
Pathogenic variants in solute carrier family 34, member 3 (SLC34A3), the gene encoding the sodium-dependent phosphate cotransporter 2c (NPT2c), cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH). Here, we report a pooled analysis of clinical and laboratory records of 304 individuals from 145 kindreds, including 20 previously unreported HHRH kindreds, in which two novel SLC34A3 pathogenic variants were identified. Compound heterozygous/homozygous carriers show above 90% penetrance for kidney and bone phenotypes. The biochemical phenotype for heterozygous carriers is intermediate with decreased serum phosphate, tubular reabsorption of phosphate (TRP (%)), fibroblast growth factor 23, and intact parathyroid hormone, but increased serum 1,25-dihydroxy vitamin D, and urine calcium excretion causing idiopathic hypercalciuria in 38%, with bone phenotypes still observed in 23% of patients. Oral phosphate supplementation is the current standard of care, which typically normalizes serum phosphate. However, although in more than half of individuals this therapy achieves correction of hypophosphatemia it fails to resolve the other outcomes. The American College of Medical Genetics and Genomics score correlated with functional analysis of frequent SLC34A3 pathogenic variants in vitro and baseline disease severity. The number of mutant alleles and baseline TRP (%) were identified as predictors for kidney and bone phenotypes, baseline TRP (%) furthermore predicted response to therapy. Certain SLC34A3/NPT2c pathogenic variants can be identified with partial responses to therapy, whereas with some overlap, others present only with kidney phenotypes and a third group present only with bone phenotypes. Thus, our report highlights important novel clinical aspects of HHRH and heterozygous carriers, raises awareness to this rare group of disorders and can be a foundation for future studies urgently needed to guide therapy of HHRH.
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Raquitismo Hipofosfatêmico Familiar , Hipofosfatemia , Humanos , Raquitismo Hipofosfatêmico Familiar/complicações , Raquitismo Hipofosfatêmico Familiar/diagnóstico , Raquitismo Hipofosfatêmico Familiar/tratamento farmacológico , Hipercalciúria/diagnóstico , Hipercalciúria/tratamento farmacológico , Hipercalciúria/genética , Rim/metabolismo , Fosfatos , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIc/genética , Proteínas Cotransportadoras de Sódio-Fosfato Tipo IIc/metabolismoRESUMO
Objectives: Rare metabolic bone diseases can present with symptoms mimicking more common rheumatological conditions including spondyloarthritis, osteoarthritis, and fibromyalgia. Increasing awareness of these rare diseases within the rheumatology community is vital to ensure that affected patients are diagnosed and appropriately treated. The literature includes several reports of tumour-induced osteomalacia initially diagnosed as rheumatic disease, but other rare diseases such as X-linked hypophosphatemia (XLH) and hypophosphatasia (HPP) also deserve attention. Here, we describe two cases of adult patients incorrectly diagnosed with ankylosing spondylitis and osteoarthritis who, upon referral to a metabolic bone disease specialist, were subsequently diagnosed with XLH and HPP, respectively, profoundly altering their management. Methods: The cases were collected from Brigham and Women's Hospital, Boston, MA, USA, and Vanderbilt University Medical Center, Nashville, TN, USA. Results: Details of the patients' respective medical and family histories are presented, and the clinical and biochemical investigations undertaken to reach the correct diagnoses are described. Conclusion: Rheumatologists should be encouraged to think beyond common rheumatological diseases when faced with symptoms such as bone pain, muscle pain, and stiffness, especially when accompanied by manifestations including atraumatic fractures, poor dentition, and hearing loss. In cases where one of these rare diseases is suspected, referral to a metabolic bone disease specialist for confirmation of diagnosis is encouraged as effective treatment options have recently become available.
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Hypophosphatasia (HPP) is a rare inborn error of metabolism that presents variably in both age of onset and severity. HPP is caused by pathogenic variants in the ALPL gene, resulting in low activity of tissue nonspecific alkaline phosphatase (TNSALP). Patients with HPP tend have a similar pattern of elevation of natural substrates that can be used to aid in diagnosis. No formal diagnostic guidelines currently exist for the diagnosis of this condition in children, adolescents, or adults. The International HPP Working Group is a comprised of a multidisciplinary team of experts from Europe and North America who have expertise in the diagnosis and management of patients with HPP. This group reviewed 93 papers through a Medline, Medline In-Process, and Embase search for the terms "HPP" and "hypophosphatasia" between 2005 and 2020 and that explicitly address either the diagnosis of HPP in children, clinical manifestations of HPP in children, or both. Two reviewers independently evaluated each full-text publication for eligibility and studies were included if they were narrative reviews or case series/reports that concerned diagnosis of pediatric HPP or included clinical aspects of patients diagnosed with HPP. This review focused on 15 initial clinical manifestations that were selected by a group of clinical experts.The highest agreement in included literature was for pathogenic or likely pathogenic ALPL variant, elevation of natural substrates, and early loss of primary teeth. The highest prevalence was similar, including these same three parameters and including decreased bone mineral density. Additional parameters had less agreement and were less prevalent. These were organized into three major and six minor criteria, with diagnosis of HPP being made when two major or one major and two minor criteria are present.
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Hipofosfatasia , Adulto , Criança , Humanos , Adolescente , Hipofosfatasia/diagnóstico , Hipofosfatasia/genética , Fosfatase Alcalina/genética , Europa (Continente) , Prevalência , MutaçãoRESUMO
Hypophosphatasia (HPP) is an inborn error of metabolism caused by reduced or absent activity of the tissue non-specific alkaline phosphatase (TNSALP) enzyme, resulting from pathogenic variants in the ALPL gene. Clinical presentation of HPP is highly variable, including lethal and severe forms in neonates and infants, a benign perinatal form, mild forms manifesting in adulthood, and odonto-HPP. Diagnosis of HPP remains a challenge in adults, as signs and symptoms may be mild and non-specific. Disease presentation varies widely; there are no universal signs or symptoms, and the disease often remains underdiagnosed or misdiagnosed, particularly by clinicians who are not familiar with this rare disorder. The absence of diagnosis or a delayed diagnosis may prevent optimal management for patients with this condition. Formal guidelines for the diagnosis of adults with HPP do not exist, complicating efforts for consistent diagnosis. To address this issue, the HPP International Working Group selected 119 papers that explicitly address the diagnosis of HPP in adults through a Medline, Medline In-Process, and Embase search for the terms "hypophosphatasia" and "HPP," and evaluated the pooled prevalence of 17 diagnostic characteristics, initially selected by a group of HPP clinical experts, in eligible studies and in patients included in these studies. Six diagnostic findings showed a pooled prevalence value over 50% and were considered for inclusion as major diagnostic criteria. Based on these results and according to discussion and consideration among members of the Working Group, we finally defined four major diagnostic criteria and five minor diagnostic criteria for HPP in adults. Authors suggested the integrated use of the identified major and minor diagnostic criteria, which either includes two major criteria, or one major criterion and two minor criteria, for the diagnosis of HPP in adults.
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Hipofosfatasia , Lactente , Adulto , Recém-Nascido , Humanos , Hipofosfatasia/diagnóstico , Hipofosfatasia/epidemiologia , Hipofosfatasia/genética , Fosfatase Alcalina/genética , Mutação , PrevalênciaRESUMO
BACKGROUND: This manuscript provides a summary of the current evidence to support the criteria for diagnosing a child or adult with hypophosphatasia (HPP). The diagnosis of HPP is made on the basis of integrating clinical features, laboratory profile, radiographic features of the condition, and DNA analysis identifying the presence of a pathogenic variant of the tissue nonspecific alkaline phosphatase gene (ALPL). Often, the diagnosis of HPP is significantly delayed in both adults and children, and updated diagnostic criteria are required to keep pace with our evolving understanding regarding the relationship between ALPL genotype and associated HPP clinical features. METHODS: An International Working Group (IWG) on HPP was formed, comprised of a multidisciplinary team of experts from Europe and North America with expertise in the diagnosis and management of patients with HPP. Methodologists (Romina Brignardello-Petersen and Gordon Guyatt) and their team supported the IWG and conducted systematic reviews following the GRADE methodology, and this provided the basis for the recommendations. RESULTS: The IWG completed systematic reviews of the literature, including case reports and expert opinion papers describing the phenotype of patients with HPP. The published data are largely retrospective and include a relatively small number of patients with this rare condition. It is anticipated that further knowledge will lead to improvement in the quality of genotype-phenotype reporting in this condition. CONCLUSION: Following consensus meetings, agreement was reached regarding the major and minor criteria that can assist in establishing a clinical diagnosis of HPP in adults and children.
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Hipofosfatasia , Adulto , Criança , Humanos , Hipofosfatasia/diagnóstico , Hipofosfatasia/genética , Mutação , Estudos Retrospectivos , Fosfatase Alcalina/genética , Genótipo , FenótipoRESUMO
BACKGROUND: Hypophosphatasia (HPP) is an inherited multisystem disorder predominantly affecting the mineralization of bones and teeth. HPP is caused by pathogenic variants in ALPL, which encodes tissue non-specific alkaline phosphatase (TNSALP). Variants of uncertain significance (VUS) cause diagnostic delay and uncertainty amongst patients and health care providers. RESULTS: The ALPL gene variant database (https://alplmutationdatabase.jku.at/) is an open-access archive for interpretation of the clinical significance of variants reported in ALPL. The database contains coding and non-coding variants, including single nucleotide variants, insertions/deletions and structural variants affecting coding or non-coding sequences of ALPL. Each variant in the database is displayed with details explaining the corresponding pathogenicity, and all reported genotypes and phenotypes, including references. In 2021, the ALPL gene variant classification project was established to reclassify VUS and continuously assess and update genetic, phenotypic, and functional variant information in the database. For this purpose, the database provides a unique submission system for clinicians, geneticists, genetic counselors, and researchers to submit VUS within ALPL for classification. An international, multidisciplinary consortium of HPP experts has been established to reclassify the submitted VUS using a multi-step process adhering to the stringent ACMG/AMP variant classification guidelines. These steps include a clinical phenotype assessment, deep literature research including artificial intelligence technology, molecular genetic assessment, and in-vitro functional testing of variants in a co-transfection model to measure ALP residual activity. CONCLUSION: This classification project and the ALPL gene variant database will serve the global medical community, widen the genotypic and phenotypic HPP spectrum by reporting and characterizing new ALPL variants based on ACMG/AMP criteria and thus facilitate improved genetic counseling and medical decision-making for affected patients and families. The project may also serve as a gold standard framework for multidisciplinary collaboration for variant interpretation in other rare diseases.
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Fosfatase Alcalina , Hipofosfatasia , Humanos , Fosfatase Alcalina/genética , Fosfatase Alcalina/química , Mutação/genética , Inteligência Artificial , Diagnóstico Tardio , Hipofosfatasia/genética , Hipofosfatasia/patologiaRESUMO
Background: Metabolic bone diseases (MBD) are typically diagnosed by non-invasive imaging and clinical biomarkers. However, imaging does not provide structural information, and biomarkers can be transiently affected by many systemic factors. Bone biopsy and pathologic evaluation is the gold standard for diagnosis of MBD, however, it is rarely utilized. We describe our technique for iliac crest tetracycline-labelled bone using a cannulated drill and assess the utility of bone biopsies to provide diagnostic and therapeutic guidance. Methods: In the 25-year period between March 1998 and January 2023, a total of 95 bone biopsies were performed on 94 patients for an osteological indication at Vanderbilt University Medical Center (VUMC). Patient demographics, bone biopsy indications, complications, diagnostic utility, and subsequent therapeutic guidance were retrospectively reviewed and analyzed. Results: The procedure had minimal complications and was well tolerated by patients. This technique provided good quality specimens for pathology, which helped establish a diagnosis and treatment change in most patients. Patients that had biopsy-guided treatment alterations showed significant increases in Dual-Energy X-ray Absorptiometry (DEXA) bone mineral density (BMD) scores post-biopsy and subsequent treatment. Conclusion: Despite scientific and technological progress in non-invasive diagnostic imaging, clinical biomarkers, and procedures for MBD, there remains a small but significant subset of patients who may benefit from inclusion of tetracycline-labelled bone biopsy into the diagnostic and therapeutic picture. Future prospective comparison studies are warranted. Mini abstract: Tetracycline-labelled bone biopsies are under-utilized. Biopsy led to a histological diagnosis and ensuing treatment alteration in most patients with significant increases in bone mineral density. The biopsy procedure used herein provided good specimens with low pain/adverse events. Bone biopsy remains a valuable tool in a small, though significant, subset of patients.
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Fibrodysplasia ossificans progressiva (FOP) is a rare disease characterized by heterotopic ossification (HO) in connective tissues and painful flare-ups. In the phase 2 LUMINA-1 trial, adult patients with FOP were randomized to garetosmab, an activin A-blocking antibody (n = 20) or placebo (n = 24) in period 1 (28 weeks), followed by an open-label period 2 (28 weeks; n = 43). The primary end points were safety and for period 1, the activity and size of HO lesions. All patients experienced at least one treatment-emergent adverse event during period 1, notably epistaxis, madarosis and skin abscesses. Five deaths (5 of 44; 11.4%) occurred in the open-label period and, while considered unlikely to be related, causality cannot be ruled out. The primary efficacy end point in period 1 (total lesion activity by PET-CT) was not met (P = 0.0741). As the development of new HO lesions was suppressed in period 1, the primary efficacy end point in period 2 was prospectively changed to the number of new HO lesions versus period 1. No placebo patients crossing over to garetosmab developed new HO lesions (0% in period 2 versus 40.9% in period 1; P = 0.0027). Further investigation of garetosmab in FOP is ongoing. ClinicalTrials.gov identifier NCT03188666 .
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Miosite Ossificante , Ossificação Heterotópica , Adulto , Humanos , Miosite Ossificante/tratamento farmacológico , Miosite Ossificante/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Ossificação Heterotópica/patologiaRESUMO
INTRODUCTION: To better understand the clinical profiles of children with hypophosphatasia (HPP) prior to treatment with enzyme replacement therapy (ERT). METHODS: Pretreatment demographics and medical histories of ERT-treated children (aged < 18 years) enrolled in the Global HPP Registry (2015-2020) were analyzed overall, by age at first HPP manifestation (< 6 months versus 6 months to 18 years) and by geographic region (United States/Canada, Europe, and Japan). RESULTS: Data from 151 children with HPP were analyzed. Sex distribution was balanced overall (52.3% female; 47.7% male) but differed in Japan (63.0% female; 37.0% male). Prior to ERT initiation, common manifestations were skeletal (67.5%) and extraskeletal, with the foremost being muscular (48.3%), constitutional/metabolic (47.0%), and neurologic (39.7%). A high proportion of children who first presented at < 6 months of age (perinatal/infantile period) had a history of bone deformity (59.3%) and respiratory failure (38.3%), while those aged 6 months to 18 years at first manifestation had a predominance of early loss of primary teeth (62.3%) and gross motor delay (41.0%). Japan reported a younger median age overall, the highest proportion of skeletal (80.4%) manifestations and growth impairment, while European data showed the highest proportion of muscular manifestations (70.7%). In the United States/Canada, skeletal and muscular manifestations were reported at the same frequency (57.4%). DISCUSSION/CONCLUSION: Prior to ERT, skeletal and extraskeletal manifestations were commonly reported in children with HPP, with differences by age at first HPP manifestation and geographical region. Comprehensive assessments of children with HPP are warranted prior to ERT initiation.
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Introduction: Hypophosphatasia (HPP) manifests in adults as fractures/pseudofractures, pain, muscle weakness, and other functional impairments. Better phenotypic disease characterization is needed to help recognize disability and treat patients with HPP. Methods: Baseline/pretreatment demographic, clinical characteristic, and patient-reported disability/health-related quality-of-life (HRQoL) data from adults (≥18 y) in the Global HPP Registry (NCT02306720) were stratified by presence of overt skeletal manifestations (skeletal group) versus muscular/pain manifestations without skeletal manifestations (muscular/pain group) and summarized descriptively. Disability was measured using the Health Assessment Questionnaire-Disability Index (HAQ-DI), and HRQoL using the 36-item Short Form Health Survey (SF-36v2). Results: Of 468 adults, 300 were classified into the skeletal group and 73 into the muscular/pain group. The skeletal group had a higher median age at baseline (50.1 vs 44.4 y; P=0.047) but a lower median age at first HPP manifestation (12.3 vs 22.1 y; P=0.0473), with more signs and symptoms (median, 4 vs 3; P<0.0001) and involved body systems (median, 3 vs 2; P<0.0001) than the muscular/pain group. More patients in the skeletal group required any use of mobility aids (22.6% vs 3.5%, respectively; P=0.001). Six-Minute Walk test distances walked were similar between groups. SF-36v2 and HAQ-DI scores were similar between groups for physical component summary (n=238; mean [SD]: 40.2 [11.0] vs 43.6 [11.2]; P=0.056), mental component summary (n=238; mean [SD]: 43.6 [11.3] vs 43.8 [11.8]; P=0.902), and HAQ-DI (n=239; median [minimum, maximum]: 0.4 [0.0, 2.7] vs 0.3 [0.0, 2.1]; P=0.22). Conclusion: Adults with HPP experience similar QoL impairment regardless of skeletal involvement. Registration: https://clinicaltrials.gov/ct2/show/NCT02306720 and https://www.encepp.eu/encepp/viewResource.htm?id=47907, identifier NCT02306720; EUPAS13514.
Assuntos
Fraturas Ósseas , Hipofosfatasia , Adulto , Humanos , Estudos Transversais , Hipofosfatasia/complicações , Hipofosfatasia/epidemiologia , Dor , Qualidade de Vida , Sistema de RegistrosRESUMO
Objective: Hypophosphatasia, an inborn error of metabolism characterized by impaired bone mineralization, can affect growth. This study evaluated relationships between anthropometric parameters (height, weight, and body mass index) and clinical manifestations of hypophosphatasia in children. Design: Data from children (aged <18 years) with hypophosphatasia were analyzed from the observational Global Hypophosphatasia Registry. Methods: Anthropometric parameters were evaluated by age group (<2 years and ≥2 years) at assessment. The frequency of hypophosphatasia manifestations was compared between children with short stature (< percentile) and those with normal stature. Results: This analysis included 215 children (54.4% girls). Short stature presented in 16.1% of children aged <2 years and 20.4% of those aged ≥2 years at assessment. Among those with available data (n = 62), height was below the target height (mean: -0.66 standard deviations). Substantial worsening of growth (mean delta height z score: -1.45; delta weight z score: -0.68) occurred before 2 years of age, while in those aged ≥2 years, anthropometric trajectories were maintained (delta height z score: 0.08; delta weight z score: 0.13). Broad-ranging hypophosphatasia manifestations (beyond dental) were observed in most children. Conclusions: Short stature was not a consistent characteristic of children with hypophosphatasia, but growth impairment was observed in those aged <2 years, indicating that hypophosphatasia might affect growth plate activity during infancy. In addition, a broad range of clinical manifestations occurred in those above and below the third percentile for height, suggesting that height alone may not accurately reflect hypophosphatasia disease burden and that weight is less affected than longitudinal growth.
RESUMO
Inactivating mutations of the gene coding for phosphate-regulating endopeptidase homolog X-linked (PHEX) cause X-linked hypophosphatemia (XLH). A novel PHEX variant, c.*231A>G; exon 13-15 duplication, has emerged as a common cause of XLH in North America, emphasizing the importance of delineating its clinical presentation. Here, a comprehensive description of a five-generation American kindred of 22 treatment-naïve individuals harboring the c.*231A>G; exon 13-15 duplication is provided. After XLH was diagnosed in the proposita, pro-active family members used social media to facilitate a timely assessment of their medical history. Most had normal height and 50% were normophosphatemic. Thirteen had been given a diagnosis other than XLH, most commonly ankylosing spondylitis, and XLH was only established after genetic testing. The prevalent phenotypic characteristics of c.*231A>G; exon 13-15 duplication were disorders of dentition (68.2%), enthesopathies (54.5%), fractures/bone and joint conditions (50%), lower-limb deformities (40.9%), hearing loss/tinnitus (40.9%), gait abnormalities (22.7%), kidney stones/nephrocalcinosis (18.2%), chest wall disorders (9.1%), and Chiari/skull malformation (4.5%). More affected males than females, respectively, had gait abnormalities (42.9% versus 13.3%), lower-limb deformities (71.4% versus 26.7%), and enthesopathies (85.7% versus 40%). Single phenotypes, observed exclusively in females, occurred in 22.7% and multiple phenotypes in 77.3% of the cohort. However, as many as six characteristics could develop in either affected males or females. Our findings will improve diagnostic and monitoring protocols for XLH. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.