VSX1 and SOD1 Mutation Screening in Patients with Keratoconus in the South of Iran

PURPOSE To investigate mutations of visual system homeobox 1 (VSX1) and superoxide dismutase 1 (SOD1) in 20 patients with keratoconus in the south of Iran. METHODS Twenty patients with keratoconus who had a positive familial history were enrolled in this study and gave informed consent for DNA analysis. Genomic DNA was extracted from peripheral blood lymphocytes. Polymerase chain reaction (PCR) was carried out to amplify exon 2 of SOD1 and its exon-intron boundary for the detection of a seven-base deletion in intron 2 of SOD1, and also all five exons of VSX1 and their exon-intron boundaries. Amplified samples were then subjected to direct DNA sequencing. RESULTS Sequencing data were compared against reference sequences using NCBI basic local alignment search tool (BLAST), which revealed that our patients had no mutations in SOD1 and VSX1. Two single-nucleotide polymorphisms (SNPs), namely in VSX1(rs58752432 and rs59089167) were found in six patients. CONCLUSION Mutations in VSX1 and SOD1 genes associated with keratoconus were not identified in our patients. Therefore, it will be necessary to investigate other chromosomal loci for potential causal mutations of keratoconus using next generation sequencing (NGS) methods in our population.