OPA1 and autosomal dominant optic atrophy: Heterozygous OPA1 mutations cause autosomal dominant optic atrophy (DOA), which is the most common form of inherited mitochondrial blindness with a minimum prevalence of 1 in 25 000 in the general population.4 Here, we report on two siblings from a consanguineous family who presented with a fatal, infantile-onset, global encephalopathy and progressive hypertrophic cardiomyopathy due to a novel homozygous mutation in the OPA1 gene.