High frequency of OPA1 mutations causing high ADOA prevalence in south-eastern Sicily, Italy.

Optic atrophy type 1 (OPA1) gene mutation causes autosomal dominant optic atrophy (ADOA, MIM #165500). Prevalence of ADOA ranges from 1:50,000 in most populations to 1:12,000 in Denmark. Seventy members of nine families were analysed for the presence of OPA1 gene mutations by polymerase chain reaction (PCR) and direct sequencing. We identified three OPA1 gene mutations in 48 patients with variable signs of optic atrophy. Two mutations, c.784-21_784-22insAluYb8 and c.876_878delTGT, were found in two different families. The third mutation, c.869G>A, was found in 28 patients from seven families. The haplotype analysis data suggested that the c.869G>A mutation is a founder mutation. Our main result suggests a higher ADOA prevalence in south-eastern Sicily than previously found in Denmark. This is because of not only the founder effect but also to the presence of three different mutations in the geographical area of the study. Our hypothesis is that a combination of social pressure because of blindness and migration factors is involved. In fact, in Siracusa, a provincial capital in south-eastern Sicily, St. Lucy, the patron saint of the blind was born and died.