RESUMO
Pseudoachondroplasia (PSACH) is an autosomal dominant disorder characterized by rhizomelic short-limbed skeletal dysplasia. The primary clinical and radiographic features include disproportionate dwarfism, joint laxity and hyperextensibility, exaggerated lumbar lordosis, and late ossification of the epiphyses. Identification of disease-causing variants in heterozygous state in COMP establishes the molecular diagnosis of PSACH. We examined 11 families with clinical features suggestive of PSACH. In nine families, we used Sanger sequencing of exons 8-19 of COMP (NM_000095.2) and in two families exome sequencing was used for confirming the diagnosis. We identified 10 de novo variants, including five known variants (c.925G>A, c.976G>A, c.1201G>T, c.1417_1419del, and c.1511G>A) and five variants (c.874T>C, c.1201G>C, c.1309G>A, c.1416_1421delCGACAA, and c.1445A>T) which are not reported outside Indian ethnicity. We hereby report the largest series of individuals with molecular diagnosis of PSACH from India and reiterate the well-known genotype-phenotype corelation in PSACH.
Assuntos
Acondroplasia , Acondroplasia/diagnóstico , Acondroplasia/genética , Proteína de Matriz Oligomérica de Cartilagem/genética , Proteínas da Matriz Extracelular/genética , Genótipo , Humanos , Proteínas Matrilinas/genética , Mutação , FenótipoRESUMO
Pyle disease (PYL) is an extremely rare disorder of irregular development of long bone. Recently, homozygous mutations in secreted frizzled-related protein 4 gene (SFRP4) gene were found to underlie this condition. Sequencing of coding regions of SFRP4 gene from an 11-year-old female with PYL was performed. A novel homozygous nonsense variant, c.183C>G (p.Y61*) was observed. Segregation analysis in the patient revealed a germline mutation, resulting in reduced protein formation. This is the second report from a fourth affected family with a SFRP4 mutation causing PYL disease.