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Introduction: Hypophosphatasia (HPP) is a rare inherited disorder, caused by mutations in the alkaline phosphatase (ALPL) gene, which encodes for the tissue non-specific alkaline phosphatase (TNSALP) isoform of alkaline phosphatase (ALP). Adult HPP is one of the mild forms that presents with unspecific signs such as osteopenia, osteomalacia and muscle involvement. Our purpose was to identify and characterize possibly misdiagnosed adult HPP patients at a clinical and biochemical level. Material and Methods: At the laboratory of Miguel Servet University Hospital we retrospectively reviewed serum ALP levels in adults over a 48-month period. The clinical records of individuals with consistently low ALP levels were reviewed to exclude secondary causes. Those with persistent hypophosphatasemia were screened for symptoms of HPP. The study participants were evaluated at biochemical and genetic levels. Results: We identified 705 ALP determinations (out of 384,000 processed) in 589 patients below the reference range (30 U/l). Only 21 patients with clinical signs and symptoms of HPP were selected for genetic testing. Finally, only 12 patients participated in the study, 83.3% of whom (10/12) harbored a pathogenic or likely pathogenic variant in a heterozygous state. The major symptoms of our cohort were the presence of musculoskeletal pain (100% of patients) and muscular weakness (83.3% patients). Conclusion: Mild HPP patients presenting with diffuse symptoms such as musculoskeletal pain may be undiagnosed or misdiagnosed as osteoporosis patients by routine diagnosis. It is important to identify these individuals, to avoid inappropriate treatment with antiresorptive drugs. [ABSTRACT FROM AUTHOR]

Summary: Nearly 10% of subjects with severe idiopathic osteoporosis present pathogenic WNT1 mutations. Clinical characteristics include a family history of osteoporosis, early adulthood onset, and fragility fractures which may evolve to pseudoarthrosis. WNT1 should be genetically screened in these patients as the phenotype is often variable and therapeutic approaches may differ. Introduction: Recent studies have shown that homozygous WNT1 gene mutations may be related to severe osteoporosis resembling osteogenesis imperfecta (OI). Conversely, heterozygous WNT1 mutations are linked to a milder phenotype of early-onset osteoporosis. Treatment with bisphosphonates is reported to be unsatisfactory. Our aim was to analyze the presence and prevalence of WNT1 mutations and the main associated clinical characteristics in subjects with primary early-onset osteoporosis. Methods: A cohort comprising 56 subjects (aged 19–60 years) with severe, early-onset osteoporosis was screened by massive parallel sequencing with a 23-gene panel. The gene panel included 19 genes known to cause OI (including the WNT1 gene), three genes related to osteoporosis, and the gene related to hypophosphatasia (ALPL). Results: We identified five patients (3 men) with heterozygous WNT1 variants. All presented severe osteoporosis with early fracture onset and a family history of fragility fractures. None presented a characteristic phenotype of OI or skeletal deformities. One patient was previously treated with bisphosphonates, presenting inadequate response to treatment and two developed pseudoarthrosis after upper arm fractures. All subjects were diagnosed in adulthood. Conclusions: Nearly 1/10 adult subjects with severe idiopathic osteoporosis may present pathogenic WNT1 mutations. Clinical characteristics commonly include a family history of osteoporosis, onset in early adulthood, marked decrease in bone mass, and prevalent fractures, particularly vertebral. WNT1 should be genetically screened in these subjects as the phenotype is often variable and the therapeutic approach may differ. The role of WNT1 mutations in the development of pseudoarthrosis should also be elucidated. [ABSTRACT FROM AUTHOR]

They showed type-I IFN polarization in COVID-toes patients compared with HC.13 We assessed whole blood type-I IFN signature based on the expression of 28 ISG (Table S7) in 24 patients, and we observed that 29.2% (7/24) of enrolled patients displayed increased ISG scores (Table S4 and Figure S1). Patients with COVID-toes evaluated before 7 days of onset of the skin lesions show statistical increase in 28-IRG score compared with patients who started later than 7 days. On the other hand, the strengths of our study are that we describe a relatively big and homogeneous cohort of young patients with COVID-toes, and to our knowledge, this is the first report that examines IFN signature in pediatric patients with COVID-toes. [Extracted from the article]

Background: More than 40 pathogenic heterozygous PRNP mutations causing inherited prion diseases have been identified to date. Recessive inherited prion disease has not been described to date. Methods: We describe the clinical and neuropathological data of inherited early-onset prion disease caused by the rare PRNP homozygous mutation R136S. In vitro PrPSc propagation studies were performed using recombinant-adapted protein misfolding cyclic amplification technique. Brain material from two R136S homozygous patients was intracranially inoculated in TgMet129 and TgVal129 transgenic mice to assess the transmissibility of this rare inherited form of prion disease. Results: The index case presented symptoms of early-onset dementia beginning at the age of 49 and died at the age of 53. Neuropathological evaluation of the proband revealed abundant multicentric PrP plaques and Western blotting revealed a ~ 8 kDa protease-resistant, unglycosylated PrPSc fragment, consistent with a Gerstmann-Sträussler-Scheinker phenotype. Her youngest sibling suffered from progressive cognitive decline, motor impairment, and myoclonus with onset in her late 30s and died at the age of 48. Genetic analysis revealed the presence of the R136S mutation in homozygosis in the two affected subjects linked to homozygous methionine at codon 129. One sibling carrying the heterozygous R136S mutation, linked to homozygous methionine at codon 129, is still asymptomatic at the age of 74. The inoculation of human brain homogenates from our index case and an independent case from a Portuguese family with the same mutation in transgenic mice expressing human PrP and in vitro propagation of PrPSc studies failed to show disease transmissibility. Conclusion: In conclusion, biallelic R136S substitution is a rare variant that produces inherited early-onset human prion disease with a Gerstmann-Sträussler-Scheinker neuropathological and molecular signature. Even if the R136S variant is predicted to be "probably damaging", heterozygous carriers are protected, at least from an early onset providing evidence for a potentially recessive pattern of inheritance in human prion diseases. [ABSTRACT FROM AUTHOR]

Hypophosphatasia, a rare genetic disease affecting bone metabolism, is characterized by decreased activity of tissue non-specific alkaline phosphatase (TNAP). The gene encoding TNAP (ALPL) has considerable allelic heterogeneity, which could explain different degrees of enzyme activity resulting in a wide clinical variability. We report the case of a preterm newborn in whom a corneal opacity was detected at birth. Blood tests performed to investigate this finding showed low alkaline phosphatase concentrations. The corneal opacity disappeared within a week but alkaline phosphatase remained persistently low. With persistently decreased levels of alkaline phosphatase, upon suspicion of hypophosphatasia, plain radiography detected changes suggestive of rickets. Sequencing of the ALPL gene revealed a heterozygous variant that has not been described in the literature to date. Our patient's condition may be an atypical neonatal form of the syndrome, with a mild phenotype, very different from the classic neonatal form, which can lead to severe skeletal disease and respiratory failure. However, it could also be an early diagnosis of the childhood form, which is associated with a better prognosis. [ABSTRACT FROM AUTHOR]

Atypical femoral fractures (AFFs) are uncommon and often related to prolonged bisphosphonate (BP) treatment. Isolated cases have been linked to mutations of tissue nonspecific alkaline phosphatase (ALPL). Moreover, mutations in the geranylgeranyl pyrophosphate synthase (GGPPS) gene, which can be inhibited by BPs, and in the enzyme of the cytochrome P450 superfamily (CYP1A1), related to the metabolism of several drugs, have also been associated with AFF development. Our aim was to analyze the incidence of ALPL, GGPS1, and CYP1A1 gene mutations in patients with AFFs and their clinical characteristics. Seventeen women with AAFs were included. All patients underwent Sanger sequencing of the ALPL, GGPS1, and CYP1A1 genes, analyzing the presence of mutations and polymorphisms in these genes. The clinical characteristics of the patients, previous treatments, ALP substrates (vitamin B6 and phosphoethanolamine), bone turnover markers, and bone mass were also analyzed. Three of 17 patients (17.6%) presented heterozygous mutations in the ALPL (p.Gly288Ala) or CYP1A1 (p.Arg136His, p.Val409Ile) genes. Only the patient with the ALPL mutation presented increased ALP substrates. Patients with CYP1A1 variants had glucocorticoid‐induced osteoporosis. All patients were previously treated with BPs during 85.5 ± 38 months, and nearly 50% were also treated with glucocorticoids. The AFF was bilateral in 35% of cases. In conclusion, ALPL and CYP1A1 mutations may be related to the development of AFF in patients treated with BPs. The evaluation of ALP substrates in patients with low ALPL levels allows the identification of patients with hypophosphatasia. The role of CYP1A1 mutations in AFF needs further study. © 2018 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency characterized by recurrent infections, hypogammaglobulinemia and poor response to vaccines. Its diagnosis is made based on clinical and immunological criteria, after exclusion of other diseases that can cause similar phenotypes. Currently, less than 20% of cases of CVID have a known underlying genetic cause. We have analyzed whole-exome sequencing and copy number variants data of 36 children and adolescents diagnosed with CVID and healthy relatives to estimate the proportion of monogenic cases. We have replicated an association of CVID to p.C104R in TNFRSF13B and reported the second case of homozygous patient to date. Our results also identify five causative genetic variants in LRBA, CTLA4, NFKB1, and PIK3R1, as well as other very likely causative variants in PRKCD, MAPK8, or DOCK8 among others. We experimentally validate the effect of the LRBA stop-gain mutation which abolishes protein production and downregulates the expression of CTLA4, and of the frameshift indel in CTLA4 producing expression downregulation of the protein. Our results indicate a monogenic origin of at least 15-24% of the CVID cases included in the study. The proportion of monogenic patients seems to be lower in CVID than in other PID that have also been analyzed by whole exome or targeted gene panels sequencing. Regardless of the exact proportion of CVID monogenic cases, other genetic models have to be considered for CVID. We propose that because of its prevalence and other features as intermediate penetrancies and phenotypic variation within families, CVID could fit with other more complex genetic scenarios. In particular, in this work, we explore the possibility of CVID being originated by an oligogenic model with the presence of heterozygous mutations in interacting proteins or by the accumulation of detrimental variants in particular immunological pathways, as well as perform association tests to detect association with rare genetic functional variation in the CVID cohort compared to healthy controls. [ABSTRACT FROM AUTHOR]

Objective Gain-of-function NLRP3 mutations cause cryopyrin-associated periodic syndrome (CAPS), with gene mosaicism playing a relevant role in the pathogenesis. This study was undertaken to characterize the genetic cause underlying late-onset but otherwise typical CAPS. Methods We studied a 64-year-old patient who presented with recurrent episodes of urticaria-like rash, fever, conjunctivitis, and oligoarthritis at age 56 years. DNA was extracted from both unfractionated blood and isolated leukocyte and CD34+ subpopulations. Genetic studies were performed using both the Sanger method of DNA sequencing and next-generation sequencing (NGS) methods. In vitro and ex vivo analyses were performed to determine the consequences that the presence of the variant have in the normal structure or function of the protein of the detected variant. Results NGS analyses revealed the novel p.Gln636Glu NLRP3 variant in unfractionated blood, with an allele frequency (18.4%) compatible with gene mosaicism. Sanger sequence chromatograms revealed a small peak corresponding to the variant allele. Amplicon-based deep sequencing revealed somatic NLRP3 mosaicism restricted to myeloid cells (31.8% in monocytes, 24.6% in neutrophils, and 11.2% in circulating CD34+ common myeloid progenitor cells) and its complete absence in lymphoid cells. Functional analyses confirmed the gain-of-function behavior of the gene variant and hyperactivity of the NLRP3 inflammasome in the patient. Treatment with anakinra resulted in good control of the disease. Conclusion We identified the novel gain-of-function p.Gln636Glu NLRP3 mutation, which was detected as a somatic mutation restricted to myeloid cells, as the cause of late-onset but otherwise typical CAPS. Our results expand the diversity of CAPS toward milder phenotypes than previously reported, including those starting during adulthood. [ABSTRACT FROM AUTHOR]

Objective Blau syndrome is characterized by noncaseating granulomatous arthritis, dermatitis, and uveitis, and results from gain-of-function NOD2 mutations. This study was undertaken to identify the genetic cause of the disease in a family with 3 members with Blau syndrome. Methods We studied a family with 3 affected members across 2 consecutive generations. The children's symptoms started early (at 6 and 7 months of age) and included polyarthritis, dermatitis, uveitis, and fever. In contrast, the father's symptoms started later (at 22 years of age) and included noncaseating granulomatous dermatitis and uveitis. We analyzed the NOD2 gene in all patients by both the Sanger method of DNA sequencing and amplicon-based deep sequencing using an Ion Torrent PGM platform. Results Sanger chromatograms revealed the heterozygous c.1001G>A transition in both children, which resulted in the p.Arg334Gln mutation that causes Blau syndrome. In contrast, the father's chromatograms revealed a small peak of adenine at the c.1001 position, suggesting the presence of a somatic NOD2 mutation. To evaluate this hypothesis, we performed amplicon-based deep sequencing using DNA from different tissues, which confirmed a variable degree (0.9-12.9%) of somatic NOD2 mosaicism. The previous detection of the NOD2 mutation in his daughters strongly suggests the presence of gonosomal (somatic plus gonadal) NOD2 mosaicism in the father. Comparative analyses with Blau syndrome patients carrying the germline p.Arg334Gln NOD2 mutation revealed late onset of the disease, a mild inflammatory phenotype, and an absence of complications in patients with NOD2 mosaicism. Conclusion This is the first description of gonosomal NOD2 mosaicism as the cause of intrafamilial recurrence of Blau syndrome. Our findings also indicate that Blau syndrome includes more diverse and milder phenotypes than previously described. [ABSTRACT FROM AUTHOR]

ABSTRACT Hypophosphatasia (HPP) is the inborn error of metabolism that features low serum alkaline phosphatase (ALP) activity caused by loss-of-function mutation(s) within the gene for the tissue nonspecific isoenzyme of ALP (TNSALP). In HPP, extracellular accumulation of inorganic pyrophosphate (PPi), a TNSALP substrate and inhibitor of mineralization, leads frequently to premature tooth loss and often to rickets or osteomalacia. In affected adults, the excess PPi sometimes also causes calcium pyrophosphate dihydrate (CPPD) deposition, PPi arthropathy, or pseudogout, or seemingly paradoxical deposition of hydroxyapatite crystals in ligaments or around joints when the condition is called calcific periarthritis (CP). We report three middle-aged sisters with CP as the only clinical manifestation of HPP. Each presented during early adult life with recurrent episodes of pain principally around the shoulders, elbows, wrists, hips, or Achilles tendon. Otherwise, they were in good health, including no history of unusual dental disease, fractures, or pseudofractures. Calcific deposits were identified in symptomatic areas principally by ultrasonographic assessment but also confirmed radiographically. All three sisters had low serum levels of total and bone-specific ALP, hyperphosphatemia, and increased serum concentrations of the TNSALP substrate pyridoxal 5′-phosphate together characteristic of HPP. Mutation analysis revealed that each carried a single unique 18-bp duplication within TNSALP (c.188_205dup18, p.Gly63_Thr68dup) as did two of their healthy sons and their mother, who was without signs of CPPD deposition or CP but had knee osteoarthritis. We find that CP can be the only complication of HPP in adults. Thus, multiple juxta-articular deposits of hydroxyapatite causing CP may be a useful sign of HPP, especially when the CP is familial. © 2014 American Society for Bone and Mineral Research. [ABSTRACT FROM AUTHOR]

Juvenile idiopathic arthritis (JIA) is a complex rheumatic disease with both autoimmune and autoinflammatory components. Recently, familial cases of systemic-onset JIA have been attributed to mutations in LACC1/FAMIN. We describe three affected siblings from a Moroccan consanguineous family with an early-onset chronic, symmetric and erosive arthritis previously diagnosed as rheumatoid factor (RF)-negative polyarticular JIA. Autozygosity mapping identified four homozygous regions shared by all patients, located in chromosomes 3, 6 (n:2) and 13, containing over 330 genes. Subsequent whole exome sequencing identified two potential candidate variants within these regions (in FARS2 and LACC1/FAMIN). Genotyping of a cohort of healthy Moroccan individuals (n: 352) and bioinformatics analyses finally supported the frameshift c.128_129delGT mutation in the LACC1/FAMIN gene, leading to a truncated protein (p.Cys43Tyrfs*6), as the most probable causative gene defect. Additional targeted sequencing studies performed in patients with systemic-onset JIA (n:23) and RF-negative polyarticular JIA (n: 44) revealed no pathogenic LACC1/FAMIN mutations. Our findings support the homozygous genotype in the LACC1/FAMIN gene as the defect underlying the family here described with a recessively inherited severe inflammatory joint disease. Our evidences provide further support to the involvement of LACC1/FAMIN deficiency in different types of JIA in addition to the initially described systemic-onset JIA. [ABSTRACT FROM AUTHOR]