Severe mitochondrial cytopathy with complete A-V block, PEO, and mtDNA deletions

Pediatr Neurol. 2002 Sep;27(3):213-6. doi: 10.1016/s0887-8994(02)00426-5.


We describe a 17-year-old male with neurologic and cardiovascular disorders characterized by complete atrioventricular block and a mitochondrial cytopathy with clinical, structural, biochemical, and molecular features shared by chronic progressive external ophthalmoplegia and Kearns-Sayre syndrome. The patient's manifestations included progressive external ophthalmoplegia, bilateral ptosis, muscle weakness, delayed development, and progressive hearing loss with multiple mitochondrial DNA deletions, including an abundant 11-kb novel deletion and reduced specific activities of respiratory complexes I, III, and IV present in skeletal muscle. Ultrastructural analysis of biopsied muscle revealed a heterogenous mixture of normal and abnormal mitochondria with unusual cristae. This unique mitochondrial DNA deletion, which eliminates the origin of mitochondrial DNA replication for the light strand, may be responsible for generating an intermediate clinical phenotype.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Biopsy
  • Chromosome Deletion*
  • Chromosome Mapping
  • Cytochrome-c Oxidase Deficiency / diagnosis
  • Cytochrome-c Oxidase Deficiency / genetics
  • DNA, Mitochondrial / genetics*
  • Diagnosis, Differential
  • Electron Transport Complex I
  • Electron Transport Complex III / deficiency
  • Electron Transport Complex III / genetics
  • Heart Block / diagnosis
  • Heart Block / genetics*
  • Heart Block / pathology
  • Humans
  • Kearns-Sayre Syndrome / diagnosis
  • Kearns-Sayre Syndrome / genetics*
  • Kearns-Sayre Syndrome / pathology
  • Male
  • Microscopy, Electron
  • Muscle, Skeletal / pathology
  • NADH, NADPH Oxidoreductases / deficiency
  • NADH, NADPH Oxidoreductases / genetics
  • Phenotype


  • DNA, Mitochondrial
  • NADH, NADPH Oxidoreductases
  • Electron Transport Complex I
  • Electron Transport Complex III