G.P.3.08 Atypical myofiber changes of a childhood mitochondrial DNA depletion syndrome with a novel thymidine kinase 2 gene mutation

Abstract

Background: The mitochondrial DNA depletion syndromes (MDS) are autosomal recessive disorders characterized by a decreased mitochondrial DNA copy number. Mutations in thymidine kinase 2 (TK2) have been associated with the myopathic form of MDS. Objective: To characterize a child with MDS that had atypical, histopathologic myofiber changes and novel mutations in the TK2 gene. Patient and methods: The child is a cognitively normal male with severe progressive muscle weakness that started at two years of age.