OPA1 and autosomal dominant optic atrophy: OPA1 mutations have been confirmed as the causative genetic defects in these syndromal forms of DOA, but until recently, these were thought to be rare manifestations among isolated families (Amati-Bonneau et al., 2003, 2005; Shimizu et al., 2003; Payne et al., 2004; Liguori, 2008).