Mutation analysis of paired box 6 gene in inherited aniridia in northern China.

[aniridia]

Aniridia is phenotypically and genetically heterogeneous . This study is to summarize the phenotypes and identify the underlying genetic cause of the paired box 6 (PAX 6 ) gene responsible for aniridia in two three -generation Chinese families in northern China .A detailed family history and clinical data were collected from patients during an ophthalmologic examination . All exons and flanking intronic sequences of the PAX 6 gene were amplified with PCR and screened for mutation with direct DNA sequencing . Haplotyping was used to confirm the mutation sequence . Real-time PCR was used to determine the PAX 6 messenger ribonucleic acid (mRNA ) level in patients with aniridia and in unaffected family members .The probands and other patients in the two families were affected with aniridia accompanied with or without congenital cataract . A heterozygous PAX 6 mutation in exon 5 (c .112 delC , p .Arg 38 GlyfsX 16 ) was identified in FAMILY-1 , which was predicted to generate a frameshift and created a premature termination codon . A heterozygous PAX 6 mutation in exon 7 (c .362 C >T , p .Ser 121 L eu ) was identified in FAMILY-2 . Each mutation cosegregated with the affected individuals in the family and did not exist in unaffected family members and 200 unrelated normal controls . The PAX 6 messenger ribonucleic acid level was about 50 % lower in patients with aniridia than in unaffected family members in FAMILY-1 .The deletion mutation (c .112 delC ) in the PAX 6 gene was first identified in a Chinese family with aniridia , congenital progressive cataract , developmental delay , or the absence of ulna . The mutation (c .362 C >T , p .Ser 121 L eu ) in the PAX 6 gene was first identified in a patient with aniridia with congenital ptosis . We summarized the variable phenotypes among the patients , which expanded the phenotypic spectrum of aniridia in a different ethnic background .