A novel de novo mutation of the mitochondrial tRNAlys gene mt.8340G>A associated with pure myopathy

Abstract Most patients with mutations in the tRNA lys gene ( MTTK ) present with symptoms from the central nervous system (CNS). We describe a 41-year-old woman with pure myopathy associated with a novel de novo mtDNA mutation, mt.8340G>A, which was heteroplasmic in muscle (53%), blood, urine and mouth epithelial cells ( MTTK .