A new mutation in the mitochondrial tRNAAla gene in a patient with ophthalmoplegia and dysphagia

We describe a new mutation in the tRNAAla gene, a T→C transition at nucleotide position 5628, in a 62-year-old woman with late onset chronic progressive external ophthalmoplegia, dysphagia and mild proximal myopathy. The mutation is heteroplasmic and disrupts a highly conserved A-U base pair within the anticodon stem of the tRNAAla. Cytochrome c oxidase-negative fibers harbor a significantly higher level of mutated mtDNA than cytochrome c oxidase-positive fibers. This is the first mutation in the tRNAAla gene which satisfies accepted criteria for pathogenicity. © 2001 Elsevier Science B.V.