A new mitochondrial point mutation in the transfer RNALys gene associated with progressive external ophthalmoplegia with impaired respiratory regulation

Abstract We report a novel heteroplasmic point mutation G8299A in the gene for mitochondrial tRNA Lys in a patient with progressive external ophthalmoplegia complicated by recurrent respiratory insufficiency. Biochemical analysis of respiratory chain complexes in muscle homogenate showed a combined complex I and IV deficiency. The transition does not represent a known neutral polymorphism and affects a position in the tRNA acceptor stem which is conserved in primates, leading to a destabilization of this functionally important domain. In vitro analysis of an essential maturation step of the tRNA transcript indicates the probable pathogenicity of this mutation. We hypothesize that there is a…