Acyl-CoA dehydrogenase 9 (ACAD9) deficiency is a rare disorder leading to a deficiency of complex I of the respiratory chain and is characterized by neurological dysfunction, hepatic failure and cardiomyopathy.
This prevalence is unknown.
Patients present predominantly with neurological, hepatic and /or cardiomyopathic disease with isolated mitochondrial respiratory complex I deficiency (see this term). Manifestations include failure to thrive, hypertrophic cardiomyopathy, exercise intolerance, liver disease and mild to severe neurological dysfunction.
ACAD9 deficiency is caused by a mutation in the ACAD9 gene (3q21.3) that encodes the protein ACAD9. This protein has only relatively recently been described but is quite widely expressed in tissues and has activity as an acyl-CoA dehydrogenase with overlapping substrate specificity with very long-chain acyl-CoA dehydrogenase (VLCAD). It also acts an assembly factor for complex I of the respiratory chain and therefore has a vital role in the production of a functioning mitochondrial respiratory chain.
The mode of inheritance is autosomal recessive and genetic counseling is possible.
Last update: February 2014