Next-generation sequencing for D47N mutation in Cx50 analysis associated with autosomal dominant congenital cataract in a six-generation Chinese family

BACKGROUND Congenital cataract is the most frequent cause of blindness during infancy or early childhood. To date, more than 40 loci associated with congenital cataract have been identified, including at least 26 genes on different chromosomes associated with inherited cataract. This present study aimed to identify the genetic mutation in a six-generation Chinese family affected with congenital cataract. METHODS A detailed six-generation Chinese cataract family history and clinical data of the family members were recorded. A total of 27 family members, including 14 affected and 13 unaffected individuals were recruited. Whole exome sequencing was performed to determine the disease-causing mutation. Sanger sequencing was used to confirm the results. RESULTS A known missense mutation, c. 139G > A (p. D47N), in Cx50 was identified. This mutation co-segregated with all affected individuals and was not observed in the unaffected family members or in 100 unrelated controls. The homology modeling showed that the structure of the mutant protein was different with that wild-type Cx50. CONCLUSIONS The missense mutation c.139G > A in GJA8 gene is associated with autosomal dominant congenital cataract in a six-generation Chinese family. The result of this present study provides further evidence that the p. D47N mutation in CX50 is a hot-spot mutation.