Absence of SIX6 Mutations in Microphthalmia, Anophthalmia, and Coloboma

PURPOSE. To investigate whether 173 patients with microphthalmia, anophthalmia, and coloboma have mutations in the eye-development gene SIX6. METHODS. The two exons of the SIX6 gene were amplified by PCR from patients' genomic DNA and directly sequenced to search for mutations. The PCR products of 75 patients were also analyzed by denaturing high-performance liquid chromatography (DHPLC). RESULTS. Six SIX6 polymorphisms were identified in the patient panel. Three of these polymorphisms change the encoded amino acid. However, all six polymorphisms were also identified in unaffected individuals. There was no statistically significant difference in genotypes between patients and control subjects. CONCLUSIONS. No evidence was found that SIX6 mutations underlie human congenital structural eye malformations.