Very Long Chain Acyl-CoA Dehydrogenase Deficiency (ACADVL)
Very long chain acyl-CoA dehydrogenase deficiency (VLCAD deficiency) is an autosomal recessive disorder that is caused by pathogenic variants in the gene ACADVL. While it is reported in individuals worldwide, it is more prevalent in the Caucasian population. VLCAD deficiency is a disorder of fatty-acid oxidization, and therefore impairs the production of energy in the body. Disease severity can vary between patients. In the most severe form, onset occurs shortly after birth and presents with cardiomyopathy. This form is associated with a high rate of early death due to multi-organ failure. In the moderate form, age of onset is in infancy or early childhood. In this form, cardiomyopathy is not as severe, but children experience episodes of low energy when they have low blood sugar, as fats cannot be efficiently broken down for energy. In the mildest form, onset is in adolescence or adulthood and is limited to muscle pain, cramps and weakness; muscle breakdown may occur following exercise. Cardiac abnormalities are not present and life expectancy is not reduced. Severe disease results when there is no functional protein made; therefore, null variants are associated with the severe form of the disease, and certain missense variants are associated with the mild form.
For information about carrier frequency and residual risk, please see the residual risk table.