Segregation patterns of a novel mutation in the mitochondrial tRNA glutamic acid gene associated with myopathy and diabetes mellitus. uri icon

Overview

abstract

  • We have identified a novel mtDNA mutation in a 29-year-old man with myopathy and diabetes mellitus. This T-->C transition at mtDNA position 14709 alters an evolutionarily conserved nucleotide in the region specifying for the anticodon loop of the mitochondrial tRNA(Glu). The nt-14709 mutation was heteroplasmic but present at very high levels in the patient's muscle, white blood cells (WBCs), and hair follicles; lower proportions of mutated mtDNA were observed in WBCs and hair follicles of all examined maternal relatives. In the patient's muscle, abnormal fibers showed mitochondrial proliferation, severe focal defects in cytochrome c oxidase activity, and absence of cross-reacting material for mitochondrially synthesized polypeptides. These fibers had higher levels of mutated mtDNA than did surrounding "normal" fibers. Although the percentage of mutated mtDNA in WBCs from family members were distributed around the percentage observed in the mothers, the pattern was different in hair follicles, where the mutated population tended to increase in subsequent generations. PCR/RFLP analysis of single hairs showed that the intercellular variations in the percentage of mutated mtDNA differed among family members, with younger generations having a more homogeneous distribution of mutated mtDNA in different hair follicles. These results suggest that the intercellular distribution of the mutated and wild-type mtDNA populations may drift toward homogeneity in subsequent generations.

publication date

  • May 1, 1995

Research

keywords

  • DNA, Mitochondrial
  • Diabetes Mellitus
  • Mitochondrial Myopathies
  • Point Mutation
  • RNA, Transfer, Glu

Identity

PubMed Central ID

  • PMC1801448

Scopus Document Identifier

  • 0028927272

PubMed ID

  • 7726154

Additional Document Info

volume

  • 56

issue

  • 5