Related Experiment Video

Updated: Jun 3, 2026

Visualization of Mitochondrial Respiratory Function using Cytochrome C Oxidase / Succinate Dehydrogenase (COX/SDH) Double-labeling Histochemistry
06:53

Visualization of Mitochondrial Respiratory Function using Cytochrome C Oxidase / Succinate Dehydrogenase (COX/SDH) Double-labeling Histochemistry

Published on: November 23, 2011

Infantile cardioencephalopathy due to a COX15 gene defect: report and review

Majid Alfadhel1, Yolanda P Lillquist, Paula J Waters

  • 1Department of Paediatrics, Children's and Women's Health Centre, Vancouver, British Columbia, Canada.

American Journal of Medical Genetics. Part A
|March 18, 2011
PubMed

Insights

Respiratory chain complex IV deficiency, a severe condition, was identified in an infant with microcephaly and cardiomyopathy. Genetic analysis revealed mutations in the COX15 gene, impacting cardiac muscle function.

Area of Science:

  • Biochemistry
  • Genetics
  • Pediatric Medicine

Background:

  • Respiratory chain complex IV (cytochrome c oxidase) is crucial for cellular energy production.
  • Deficiency in complex IV can lead to severe, multi-systemic disorders.
  • Neonatal onset of complex IV deficiency often presents with a rapidly progressive and fatal course.

Observation:

  • A female infant presented with microcephaly, encephalopathy, persistent lactic acidosis, and hypertrophic cardiomyopathy.
  • The clinical course was rapidly progressive and fatal within the neonatal period.
  • Postmortem examination revealed marked complex IV deficiency specifically in cardiac muscle.

Findings:

  • Complex IV activity was significantly reduced in the heart but only slightly decreased in skeletal muscle.
  • Molecular investigations identified compound heterozygosity for two pathogenic mutations in the COX15 gene.
  • This genetic profile explains the tissue-specific severity of the deficiency.

Implications:

  • This case highlights the critical role of COX15 in cardiac function and development.
  • Understanding genotype-phenotype correlations in COX15-related complex IV deficiency is essential for diagnosis.
  • Further research into COX15 mutations can inform potential therapeutic strategies for mitochondrial disorders.

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