MiP2005: Session 10 - Young Investigator Presentation

Mitochondrial Physiology Network 10.9: 118-119 (2005) - download pdf


Importance of the mitochondrial genetic background in the mtDNA mutations expression: Implication in mitochondrial diseases.

Denis Pierron1, C Rocher2, R Rossignol2, P Murail1, D Thoraval3, T Letellier2

U 688 - INSERM, Physiopathologie Mitochondriale, Université Victor Segalen Bordeaux 2, Bordeaux, France. - d.pierron@anthropologie.u-bordeaux1.fr

    The mitochondrial genetic diseases can be caused by more than 50 mtDNA mutations and 200 rearrangements. It has been already observed that several distinct mtDNA mutations can product the same disease and reciprocally several diseases can be related to the same mutation. These observations highlight the problem of the variability of the expression of these mutations. Several hypotheses such as differences in the “threshold effect”, or heteroplasmy levels have been proposed to explain this variability. However, differences in the mitochondrial genetic background is another hypothesis, but this notion is difficult to investigate with traditional genetic approaches.

    The recent progress in molecular anthropology has lead to the possibility of the definition of monophyletic groups of mitochondrial DNA. Indeed, the analysis of mtDNA sequences has shown a high degree of homogeneity among European populations with 99% of European mtDNAs fall into one of ten haplogroups (H, I, J, K, M, T, U, V, W or X). These “haplogroups” can be a useful tool for such genetic/epidemiology study. For the moment, only few studies are published on the relationships between haplogroups and mitochondrial diseases and concern few of these pathologies. In addition, these works often concern a small number of patients, which do not allow a clear statistical analysis.

    Three laboratories of Bordeaux1,2,3 in collaboration with the French network of the mitochondrial diseases work to define the haplogroups of most of 500 French patients and to highlight the importance of the mitochondrial genetic background in the mtDNA mutations expression.

1        Laboratoire d’anthropologie des populations du passé UMR CNRS 5809/ Université Bordeaux 1

2        Laboratoire de « Pysiopathologie Mitochondriale » INSERM U688/ Université Victor Segalen-Bordeaux 2

3        Laboratoire de Biologie Moléculaire et Séquençage  IBGC UMR CNRS 5095/Université Victor Segalen-Bordeaux 2

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