Isovaleric acidemia (IVA) is a branched-chain amino acidemia characterized by a defect in the catabolism of leucine and the build-up of isovaleryl CoA in the body. A characteristic feature of the acute state of the condition is a distinctive odor of sweaty feet, caused by the accumulation of isovaleric acid. Other symptoms, such as loss of appetite, lethargy, vomiting, hypotonia, seizures, and cardiac abnormalities are similar to other organic acidemias. The condition is estimated to affect 1 in every 250,000 individuals.
Diagnosis, as in the case of other organic acidemias, relies on chromatography followed by mass spectrometric analysis. Tandem Mass Spectrometry of hell stick dried blood spots is one of the most widely used methods, in which presence of elevated levels of the compound acylcarnitine are looked out for. The result of TM is combined with that of urinalysis to make a confirmed diagnosis. The urinalysis is especially required to rule out 2-methylbutyryl CoA dehydrogenase deficiency. It is also possible to measure the level of isovalyrylglycine in the amniotic fluid, or IVD activity in chorionic villi samplings, as a prenatal diagnostic method. The first step in treatment is to reduce the dietary intake of leucine. Infections need to be handled carefully, since the leucine stored in proteins tends to be released during such states. It is important to monitor the growth, development, and biochemical parameters of affected children at frequent intervals. Early detection and proper management results in normal development.