A novel PAX6 mutation in a Chinese family with congenital aniridia

Abstract

Background Aniridia is a rare congenital hereditary eye disease.Studies determined that PAX6 gene mutation is closely associated with congenital aniridia, but the mutation locus are varied. Objective This study was to identify virulence mutation locus of PAX6 gene of a Chinese family pedigree with autosomal dominant aniridia. Methods A Chinese family affected with autosomal dominant aniridia was collected and examined in Affiliated First Hospital of Zhengzhou University in August 2014.Periphery blood of 10 ml was collected from all the families and 100 unrelated health controls.The genomic DNA was extracted by standardized phenol-chloroform method, and all exons and splicing junctions of PAX6 were amplified by PCR.Real-time fluorescence quantitative PCR was performed to examine the relative expression of PAX6 mRNA in patients and normal phenotype families and health controls.This study protocol was approved by Ethic Committee of Affiliated First Hospital of Zhengzhou University and complied with Helsinki Declaration.Written informed consent was obtained from subjects or custodian before any medical examination. Results This Chinese family inclued 3 generations and 9 members, with a classic autosomal dominant inheritance mode.Five patients were found, showing the absence of iris and cataract in 3 adult patients and only absence of the iris in 2 children, and other 4 members showed the normal phenotype.A novel heterozygous PAX6 deletion mutation c. 796 del G (p.A266 fs) (GenBank ID: KP255960) in exon 10 was exclusively found in all affected individuals but not in any of the unaffected families or unrelated health controls.PAX6 mRNA level in lymphocytes was about 50% lower in aniridia patients than in unaffected family members, indicating that this mutation caused nonsense-mediated mRNA decay. Conclusions A novel deletion mutation in PAX6 gene results in an abnormal PAX6 COOH-terminal extension in the Chinese aniridia family.This finding expands the mutation spectrum of PAX6 gene. Key words: Aniridia/genetics; Chromosomes, human, pair 11/genetics; Paired box transcription factors/genetics; Base sequence; Frameshift mutation; Pedigree; Chinese/genetics