Fundus changes in patients with the mitochondrial DNA point mutation at position 3243.

The A3243G transition in the mitochondrial DNA is commonly associated with the syndrome of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS). Previously, atypical pigmentary retinopathy has been described in patients with this syndrome and in patients with other phenotypes of the same mitochondrial defect. Maternally inherited diabetes mellitus and deafness has been recognized as a distinct clinical presentation of the mitochondrial point mutation at position 3243, and recently a pattern dystrophy has been identified as a characteristic ocular abnormality in these patients. The finding of a macular pattern dystrophy in patients with diabetes should therefore lead to screening for this aberrant mitochondrial genome.