Presentation ranges from mild to life-threatening. Patients with severe cases present a few days after birth. Initial symptoms include poor feeding, vomiting, and lethargy, but may progress to seizures, coma, and possibly death. A characteristic sign is the unique odor of sweaty feet caused by buildup of isovaleric acid. In less severe cases, symptoms present in childhood gradually over time. Children experience failure to thrive and delayed development. More severe complications may be caused by fasting, infections, or eating an increased amount of protein. Some patients are asymptomatic.
IVA, also known as isovaleric acid-CoA dehydrogenase deficiency or IVD deficiency, is caused by mutations in the IVD gene inherited in an autosomal recessive pattern.
Treatment consists of maintaining a low-protein diet. Protein intake can typically be increased over time depending on patient age, growth, development, metabolic control, and amino acid plasma levels, and diet is typically supplemented with a leucine-free amino acid mixture.
If left untreated, IVA can lead to brain damage and possibly death. About half of patients who present in the newborn period will not survive. However, if the condition is identified and treated early in the patient's life, there is usually a good prognosis. The majority of patients who survive develop normally.
For more information, see OMIM.
E71.110 – Isovaleric acidemia
87827003 – Isovaleryl-coenzyme A dehydrogenase deficiency