Mutational screening of six genes in Chinese patients with congenital cataract and microcornea

PURPOSE To identify mutations in 6 genes of 9 Chinese families with congenital cataract and microcornea. METHODS Nine unrelated families with congenital cataract and microcornea were collected. Cycle sequencing was used to detect variants in the coding and adjacent regions of the crystallin alpha A (CRYAA), crystallin beta B1 (CRYBB1), crystallin beta A4 (CRYBA4), crystallin gamma C (CRYGC), crystallin gamma D (CRYGD), and gap junction protein alpha 8 (GJA8) genes. RESULTS Upon complete analysis of the 6 genes, three mutations in 2 genes were detected in 3 families, respectively. These mutations were not present in 96 normal controls. Of the three mutations, two novel heterozygous mutations in GJA8, c.136G>A (p.Gly46Arg) and c.116C>G (p.Thr39Arg), were found in two families with congenital cataract and microcornea. The rest one, a heterozygous c.34C>T (p.Arg12Cys) mutation in CRYAA, was identified in three patients from a family with nuclear cataract, microcornea with axial elongation. No mutation in the 6 genes was detected in the remaining 6 families. CONCLUSIONS Mutations in GJA8 and CRYAA were identified in three families with cataract and microcornea. Elongation of axial length accompanied with myopia was a novel phenotype in the family with the c.34C>T mutation in CRYAA. Our results expand the spectrum of GJA8 mutations as well as their associated phenotypes.