cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency 3

Cardioencephalomyopathy, fatal infantile, due to cytochrome c oxidase deficiency 3 is a severe disorder that affects both the heart and the brain in early infancy. The condition is caused by pathogenic variants in the COA5 gene, which play a critical role in the function of mitochondrial complex IV. It typically presents in infancy, with affected children showing signs of cardiac and neurological dysfunction. Precise prevalence data are not available, and the condition is considered extremely rare.

The clinical presentation is marked by a complete deficiency in the activity of mitochondrial complex IV, hypertrophic cardiomyopathy, and proliferation of mitochondria in cardiomyocytes, with these features observed in all affected individuals. These findings are typically identified during an evaluation for cardiac dysfunction in infancy. Although the core features are consistently present, not all individuals may experience every potential complication, and severity can vary between cases.

This condition is caused by mutations in the COA5 gene, which is essential for proper mitochondrial function, particularly in the respiratory chain complex IV. It is inherited in an autosomal recessive pattern, meaning that an affected child has received one mutated copy of the gene from each parent. Families with a history of this condition may benefit from genetic counseling to discuss carrier testing and options for family planning.

Currently, management focuses on supportive care and symptom management, as there are no approved treatments specifically targeting this condition. A multidisciplinary team approach is central to care, with efforts directed at managing cardiac complications and providing general supportive therapies. Patients and families are encouraged to discuss treatment options with their healthcare team and to consider genetic counseling as part of the overall management plan.

The prognosis for cardioencephalomyopathy due to cytochrome c oxidase deficiency 3 is poor, with the condition being fatal during infancy in many cases. Outcomes vary depending on the severity of cardiac dysfunction and other complications, and although the course is typically rapid, standards of care continue to evolve. Outcomes described in medical literature continue to evolve as standards of care improve. Families often find it helpful to connect with genetic counselors and specialists experienced in mitochondrial disorders to navigate the challenges of this condition.