Isovaleric Acidemia (IVD)
Isovaleric acidemia is an autosomal recessive disorder caused by pathogenic variants in the IVD gene, which has the highest prevalence in the Caucasian and Asian populations. There are two recognized forms of isovaleric acidemia: the neonatal form and the chronic form. In the neonatal form, patients experience devastating metabolic acidosis at birth. This acidosis causes seizures, lethargy, hepatomegaly, vomiting, coma, and, if untreated, death. In the chronic form, patients will not have any symptoms in between crises. When they undergo stress such as fasting or extreme energy need, however, patients are at risk of developing severe ketoacidosis. During these crises, they may develop any or all of the symptoms outlined in the neonatal form; this can prove fatal without intervention. If they are closely monitored by an experienced medical team, patients may live a typical lifespan. There have been no reported genotype-phenotype correlations.
For information about carrier frequency and residual risk, please see the Expanded Carrier Screen brochure.