Diabetes Care, Vol 20, Issue 11 1731-1737, Copyright © 1997 by American Diabetes Association
Phenotypic expression of diabetes secondary to a T14709C mutation of mitochondrial DNA. Comparison with MIDD syndrome (A3243G mutation): a case report
BH Vialettes, V Paquis-Flucklinger, JF Pelissier, D Bendahan, H Narbonne, P Silvestre-Aillaud, MF Montfort, M Righini-Chossegros, J Pouget, PJ Cozzone and C Desnuelle
Laboratoire de Neurobiologie Cellulaire, Faculte de Medecine, Centre National de la Recherche Scientifique (CNRS) Unite Mixte de Recherche (UMR) 6549, France.
OBJECTIVE: To analyze the clinical and biochemical features of a recently
described point mutation of mitochondrial DNA associated with diabetes.
This mutation, characterized by a T14709C transition of a highly conserved
nucleotide in the region coding for the glutamic acid tRNA, is
heteroplasmic. RESEARCH DESIGN AND METHODS: The phenotypic expression in
the insulin-requiring diabetic proband from the pedigree was compared to
that of diabetic probands from three families with the classic A3243G mtDNA
mutation (maternally inherited diabetes and deafness [MIDD] syndrome). The
same investigations to evaluate pancreatic neurosensorial and muscle
involvement were performed in all four patients. RESULTS: The natural
courses of the diabetes and the hearing defects were not different between
the two mutations. The patient with the 14,709 mutation, however, exhibited
a milder alteration of pigmentary epithelium of retina and a much more
severe muscle involvement, as attested by the clinical expression and the
concurrent anomalies of muscle energy production evidenced by 31P magnetic
resonance spectroscopy, confirming the profound impairment of oxidative
processes. CONCLUSIONS: This novel mutation has to be added to the other
known mtDNA anomalies in order to ascribe some diabetes suspected to arise
from mitochondrial defects to this nosological framework.