Detection of mitochondrial DNA deletions in human skin fibroblasts of patients with Pearson's syndrome by two-color fluorescence in situ hybridization

J Histochem Cytochem. 1997 Jan;45(1):55-61. doi: 10.1177/002215549704500108.


Pearson's marrow/pancreas syndrome is a disease associated with a large mitochondrial DNA (mtDNA) deletion. The various tissues of a patient contain heteroplasmic populations of wild-type (WT) and deleted mtDNA molecules. The clinical phenotype of Pearson's syndrome is variable and is not correlated with the size and position of the deletion. The histo- and cytological distribution of WT and deleted mtDNA molecules may be factors that correlate with the phenotypical expression of the disease. Here we introduce a new application of two-color FISH to visualize WT and deleted mtDNA simultaneously in a cell population of in vitro cultured skin fibroblasts of two patients with Pearson's syndrome. At the third passage of culturing, fibroblasts showed a remarkable heterogeneity of WT and deleted mtDNA: about 90% of the cells contained almost 100% WT mtDNA, and 10% of the cells contained predominantly deleted mtDNA. At the tenth passage of culturing, fibroblasts showed a reduction of intercellular heteroplasmy from 10% to 1%, while intracellular heteroplasmy was maintained. This new approach enables detailed analysis of distribution patterns of WT and deleted mtDNA molecules at the inter- and intracellular levels in clinical samples, and may contribute to a better understanding of genotype-phenotype relationships in patients with mitochondrial diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone Marrow Diseases / genetics*
  • Cells, Cultured
  • DNA, Mitochondrial / analysis
  • DNA, Mitochondrial / genetics*
  • Fibroblasts / chemistry
  • Humans
  • In Situ Hybridization, Fluorescence*
  • Mitochondria / genetics
  • Oligonucleotide Probes
  • Pancreatic Diseases / genetics*
  • Sequence Deletion*
  • Skin / chemistry*
  • Syndrome


  • DNA, Mitochondrial
  • Oligonucleotide Probes