Purpose To identify a mutation in PAX6 and characterize clinical features of severe ocular malformation in a Chinese family with congenital aniridia.

Methods We studied two patients with aniridia from a Chinese family. All patients and non-carriers in this family underwent full ophthalmologic, general and urinary examinations. Total genomic DNA was isolated from peripheral blood of two aniridia patients, and all the exons of the Paired Box gene 6(PAX6) were analyzed amplified by a polymerase chain reaction, and subsequently analyzed by direct sequencing of PCR products. Variations detected were further evaluated in available family members as well as in controls by direct sequencing.

Results The patients had bilateral congenital nystagmus, microphthalmus, anterior polar cataract, absence of iris tissue, and foveal hypoplasia with severely reduced visual acuity. A heterozygous PAX6 mutation in exon 6 c.662G>A was create a premature termination codon. None of the observed sequence alteration was found in normal controls. This mutation, which affects highly conserved amino acid, has not been previously reported.

Conclusions We identified a PAX6 mutation in a family with severe ocular malformation. Our study enriches our knowledge of genotype-phenotype relation due to PAX6 mutations.