Purpose:
To identify the causative paired box 6 (PAX6) mutation in a family with autosomal dominant aniridia associated to congenital ptosis.
Methods:
A family with autosomal dominant aniridia with three affected individuals in two generations was investigated for the causative PAX6 mutation. They presented nistagmus; foveal hypoplasia, corneal opacity, atrophic optic disk and congenital ptosis. Genomic DNA was obtained from peripheral blood by proteinase K/phenol extraction method. PAX6 gene molecular analysis was performed by PCR amplification of the fourteen exons (Table). PCR products were directly sequenced with both sense and antisense primers using Big Dye® Terminator Cycle Sequencing Kit V3.1 Ready Reaction (ABI PRISM/PE Biosystems). Sequences were obtained in an ABI 3700 Sequencer (ABI PRISM/PE Biosystems) and were compared to the PAX6 normal sequence (ENSEMBL - ENSG00000007372) using Chromas (reduced version-free software) and CLC Sequence Viewer v.6.0 (free software).
Results:
The three patients evaluated are heterozygous for the insertion of a timine in exon 14. This insertion changes the stop codon to a leucine codon.
Conclusions:
To date only four families with aniridia were described previously in Brazil and this is the first description including mutation in PAX 6 gene. This mutation has been already described in other patients with aniridia and it is known as run-on mutation since it eliminates the natural translation termination signal.
Keywords: anterior segment • gene/expression • macula/fovea