What Your Test Results Mean:

Although carriers do not typically exhibit symptoms of the disease, all carriers are at an increased risk for having a child born with isovaleric acidemia. Testing your partner and seeing a genetic counselor for further information on your risk assessment is recommended.

Disease Explained:

Isovaleric acidemia is an inherited metabolic condition characterized by the body's inability to break down the amino acid leucine due to having inadequate levels of the enzyme isovaleryl-CoA dehydrogenase. Due to the lack of this enzyme, proteins cannot be processed properly and organic acids, including isovaleric acid, build-up in the body, which can cause a variety of health problems.

Initial symptoms may be present shortly after birth and can include vomiting, poor feeding, and lethargy. The symptoms have the ability to progress to further medical concerns such as seizures, coma, and ultimately potentially causing death. The build-up of isovaleric acid causes a distinct characteristic of the disorder: the odor of sweaty feet during acute illness. Other medical problems that characterize this disorder is the failure to grow and gain weight at a normal rate (failure to thrive), as well as exhibiting delayed development. Treatment consists of restricting protein in the diet, more commonly protein that contains the amino acid leucine. Avoiding protein-rich foods, infection, and fasting (going for long periods without eating) can help prevent symptoms of the disease.

How the Genetics Works:

Isovaleric acidemia is an autosomal recessive disorder caused by pathogenic variants in the IVD gene. Carriers of isovaleric acidemia have a variant in one copy of the IVD gene while individuals with the disorder have variants in both copies their genes, one inherited from each parent. Risk for two carriers to have a child with the disorder is 25%.