PAX6 gene screening in a large Iranian pedigree with aniridia

Aniridia is a rare developmental eye disorder characterized by complete or partial iris hypoplasia. Aniridia is associated with multiple other ocular changes that affect the cornea, anterior chamber, iris, lens, retina, macula and optic nerve. Most cases are associated with dominantly inherited mutations or deletions of the PAX6 gene. PAX6 that encodes a paired box transcriptional factor is considered as the master regulator in the eye development. To reveal the underlying genetic defect in a four-generation Iranian family with aniridia, we carried out a genetic screening of PAX6.Methods: Complete ophthalmic examinations were performed in available affected family members. Genomic DNA was extracted from peripheral blood leukocytes using the standard salting out method and all PAX6 exons and their flanking regions were amplified by PCR. Candidate variation was screened for segregation in the pedigree by Sanger sequencing. The in silico bioinformatics tools were used to predict and score the deleterious effects of the identified nucleotide change on the protein product.Results: All patients were diagnosed with isolated aniridia without any systemic involvement. p.Leu107HisfsX16 mutation on PAX6 gene was detected. The frameshift mutation leads to early termination of the amino acid coding, which is expected to affect the protein’s function.Conclusion: To the best of our knowledge, it is the first report on genetics of aniridia in Iran. Segregation analysis and bioinformatics predictions all support the proposition that the observed PAX6 mutation is cause of aniridia in the pedigree.