[Clinical features and genetic analysis of two Chinese patients with Coffin Siris syndrome-1].

To explore the genetic basis for two unrelated patients with global developmental delay and coarse facial features.Clinical data and family history of the two pedigrees were collected. Whole exome sequencing and Sanger sequencing were carried out to detect potential variants.The two patients have presented with global developmental delay, coarse facies, muscular hypotonia, congenital heart disease, and pectus excavatum, and were found to harbor two de novo loss-of-function variants of the ARID1B gene, namely c.3586delC (p.Gln1196Serfs*15) and c.4954_4957delACGT (p.Thr1652Glyfs*31). Both variants were unreported previously.The nonsense variants of the ARID1B gene probably underlay the etiology in these patients. Above finding has enriched the genotypic and phenotypic spectrum of the disease and provided a basis for prenatal diagnosis.