Two siblings with Bardet-Biedl syndrome caused by mutations in BBS10 : the first case identified in Korea

Bardet-Biedl syndrome (BBS) is a rare ciliopathy generally inherited with an autosomal recessive pattern. BBS is characterized by 6 primary features namely retinal dystrophy, obesity, postaxial polydactyly, renal dysfunction, learning difficulties, and hypogonadism and a wide range of secondary features. To date, mutations in 16 genes have been identified as causative factors for BBS. Among them, the BBS1 and BBS10 genes are major disease-causing genes, and each of these gene mutations presents in more than 20% of all BBS patients. Genotype-phenotype correlations have not been observed in BBS, and there can be phenotypic overlap between BBS and other ciliopathies. In Korea, no molecular, genetically confirmed case of BBS has been reported to date. Herein, we describe the case of the first Korean siblings with BBS resulting from 2 BBS10 gene mutations who showed typical clinical phenotypes, including retinal dystrophy, obesity, intellectual disability, cystic tubular disease, and postaxial polydactyly.