Due to its volatility (thus producing the odor), it is lost prior to and during specimen preparation for urine organic acid determination. In contrast, patients with 2-methylbutyryl-CoA dehydrogenase deficiency have 2-methylbutyrate and 2-methylbutyrylglycine in their urine. Prenatal diagnosis is possible by measuring isovalerylglycine in amniotic fluid and by measuring isovaleryl-CoA dehydrogenase enzyme activity in chorionic villus specimens or cultured amniocytes. The activity can also be measured in fibroblasts and leukocytes.
Treatment of patients with isovaleric acidemia involves reducing protein intake, particularly the branched-chain amino acid leucine. During an acute episode, aggressive use of glucose and electrolytes is necessary. Glycine supplementation has proven beneficial because this amino acid is conjugated to isovalerate, forming the less harmful isovalerylglycine. Carnitine treatment is similarly effective. Strict dietary control and aggressive treatment have resulted in normal development in some patients. However, many patients with isovaleric acidemia show neurologic abnormalities from acute illness.
This disorder most often follows an autosomal recessive inheritance pattern. With recessive disorders affected patients usually have two copies of a disease gene (or mutation) in order to show symptoms. People with only one copy of the disease gene (called carriers) generally do not show signs or symptoms of the condition but can pass the disease gene to their children. When both parents are carriers of the disease gene for a particular disorder, there is a 25% chance with each pregnancy that they will have a child affected with the disorder.