RESUMO
Johanson-Blizzard syndrome (JBS) is a rare, autosomal recessive disorder characterized by exocrine pancreatic insufficiency, typical facial features, dental anomalies, hypothyroidism, sensorineural hearing loss, scalp defects, urogenital and anorectal anomalies, short stature, and cognitive impairment of variable degree. This syndrome is caused by a defect of the E3 ubiquitin ligase UBR1, which is part of the proteolytic N-end rule pathway. Herein, we review previously reported (n = 29) and a total of 31 novel UBR1 mutations in relation to the associated phenotype in patients from 50 unrelated families. Mutation types include nonsense, frameshift, splice site, missense, and small in-frame deletions consistent with the hypothesis that loss of UBR1 protein function is the molecular basis of JBS. There is an association of missense mutations and small in-frame deletions with milder physical abnormalities and a normal intellectual capacity, thus suggesting that at least some of these may represent hypomorphic UBR1 alleles. The review of clinical data of a large number of molecularly confirmed JBS cases allows us to define minimal clinical criteria for the diagnosis of JBS. For all previously reported and novel UBR1 mutations together with their clinical data, a mutation database has been established at LOVD.
Assuntos
Anus Imperfurado/genética , Displasia Ectodérmica/genética , Transtornos do Crescimento/genética , Perda Auditiva Neurossensorial/genética , Hipotireoidismo/genética , Deficiência Intelectual/genética , Mutação/genética , Nariz/anormalidades , Pancreatopatias/genética , Ubiquitina-Proteína Ligases/genética , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/patologia , Anus Imperfurado/patologia , Bases de Dados Genéticas , Nanismo/genética , Nanismo/patologia , Displasia Ectodérmica/patologia , Transtornos do Crescimento/patologia , Perda Auditiva Neurossensorial/patologia , Humanos , Hipotireoidismo/patologia , Deficiência Intelectual/patologia , Nariz/patologia , Pancreatopatias/patologia , FenótipoRESUMO
BACKGROUND/AIMS: Calcium homeostasis requires regulated cellular and interstitial systems interacting to modulate the activity and movement of this ion. Disruption of these systems in the kidney results in nephrocalcinosis and nephrolithiasis, important medical problems whose pathogenesis is incompletely understood. METHODS: We investigated 25 patients from 16 families with unexplained nephrocalcinosis and characteristic dental defects (amelogenesis imperfecta, gingival hyperplasia, impaired tooth eruption). To identify the causative gene, we performed genome-wide linkage analysis, exome capture, next-generation sequencing, and Sanger sequencing. RESULTS: All patients had bi-allelic FAM20A mutations segregating with the disease; 20 different mutations were identified. CONCLUSIONS: This autosomal recessive disorder, also known as enamel renal syndrome, of FAM20A causes nephrocalcinosis and amelogenesis imperfecta. We speculate that all individuals with biallelic FAM20A mutations will eventually show nephrocalcinosis.
Assuntos
Amelogênese Imperfeita/genética , Proteínas do Esmalte Dentário/genética , Predisposição Genética para Doença/genética , Mutação , Nefrocalcinose/genética , Adolescente , Adulto , Amelogênese Imperfeita/complicações , Amelogênese Imperfeita/patologia , Criança , Consanguinidade , Exoma/genética , Saúde da Família , Feminino , Genes Recessivos/genética , Estudo de Associação Genômica Ampla , Humanos , Masculino , Pessoa de Meia-Idade , Nefrocalcinose/complicações , Nefrocalcinose/patologia , Linhagem , Análise de Sequência de DNA/métodos , Síndrome , Adulto JovemRESUMO
Epidemiological variables in oral clefts were examined in a cohort of patients with congenital malformations from the canton of Vaud in Switzerland during the years 1990-1999. Among 77'259 newborns or foetuses, 144 cases of oral clefts were identified in the Registre Vaudois des Anomalies Congénitales (RVAC), yielding a total prevalence of 18.6 per 10'000. These clefts consisted of 84 (58%) cases of cleft lip with or without cleft palate (CL/P) and 60 (42%) cases of cleft palate only (CP). Associated anomalies were found in 45% of cases. Our results are compared with previous reports in other parts of Europe.