No association of the mitochondrial DNA A12308G polymorphism with increased risk of stroke in patients with the A3243G mutation.

This article focuses on a study that finds no association of the mitochondrial DNA A 12308G polymorphism with increased risk of stroke in patients with the A3242G mutation. Only 50% of patients carrying the A3243G mutation have stroke-like episodes and the reason for this clinical variability remains poorly understood. It is responsible for 80% of cases of MELAS, mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes, and is also associated with several other phenotypes including maternally inherited diabetes and deafness and chronic progressive external ophthalmoplegia. Researchers carried out a large, multicentre study to investigate the A12308G polymorphism in a group of 107 unrelated family index cases harbouring the A3243G mutation.