Increased risk of stroke in patients with the A12308G polymorphism in mitochondria

Factors which increase the risk of stroke in patients with the A3243G (mito chondrial encephalomyopathy, lactic acidosis, and stroke [MELAS]) mutation in human mitochondrial DNA are unclear. Previous work on lung-cancer cells with an A3243G mutation showed that a mutation In the mitochondrial transfe r gene for leucine tRNA(Leu(CUN)) was able to ameliorate the A3243G-induced biochemical phenotype. We analysed the tRNA(Leu(CUN)) gene in 48 unrelated A3243G cases. We showed that a polymorphism, A12308G, in tRNA(Leu(CUN)) in creases the risk of developing stroke in patients with the A3243G mutation (relative risk=2.17). This may have implications for genetic counselling.