Organic Acidemias

Abstract

Organic acidemias (OA) are defects in the degradation of leucine, isoleucine, and valine. OA can present as either a severe neonatal onset form (poor feeding, vomiting, lethargy, tachypnea, progressing to acidosis, respiratory distress, coma, death) or late-onset (usually recurrent ketoacidosis or lethargy with catabolic stress). Nutrition treatment involves use of propiogenic amino acid free medical foods and restriction of natural protein in PROP and MMA and protein restriction with or without leucine-free medical food and supplemental glycine in IVA. Outcomes in PROP and MMA have been guarded with frequent neurological complications, renal dysfunction, cardiomyopathy and optic atrophy but are improving with earlier identification and treatment, as well as with liver or liver-kidney transplantation; outcomes in IVA are often normal.