Phenotypic variability of mitochondrial disease caused by a nuclear mutation in complex II

Mol Genet Metab. 2006 Nov;89(3):214-21. doi: 10.1016/j.ymgme.2006.05.003. Epub 2006 Jun 23.

Abstract

We report a patient with relatively mild Leigh syndrome and mitochondrial respiratory chain complex II deficiency caused by a homozygous G555E mutation in the nuclear encoded flavoprotein subunit of succinate dehydrogenase. This mutation has previously been reported in a lethal-infantile presentation of complex II deficiency. Such marked phenotypic heterogeneity, although typical of heteroplasmic mutations in the mitochondrial genome, is unusual for nuclear mutations. Comparable activities and stability of mitochondrial respiratory chain enzymes were demonstrated in both patients, so other reasons for the phenotypic variability are considered.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Nucleus / metabolism*
  • Child
  • Child, Preschool
  • DNA Mutational Analysis
  • DNA, Complementary / metabolism
  • Electron Transport Complex II / chemistry
  • Electron Transport Complex II / genetics*
  • Electron Transport Complex II / metabolism
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Hypothalamus, Middle / diagnostic imaging
  • Infant
  • Magnetic Resonance Imaging
  • Male
  • Mitochondrial Diseases / genetics*
  • Molecular Sequence Data
  • Mutation / genetics*
  • Phenotype*
  • Protein Structure, Secondary
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Radiography
  • Ubiquinone / metabolism

Substances

  • DNA, Complementary
  • Protein Subunits
  • Ubiquinone
  • Electron Transport Complex II