Renal Involvement in Methylmalonic Aciduria

Isolated methylmalonic acidemia/aciduria (MMA) is a rare metabolic disorder caused by complete or partial deficiency of the enzyme methylmalonyl-CoA mutase (mut0 or mut– enzymatic subtype, respectively), a defect in the synthesis or transport of its cofactor, adenosyl-cobalamin (cblA, cblB, or cblD-MMA), or deficiency of the enzyme methylmalonyl-CoA epimerase.1–5 The clinical spectrum of isolated MMA ranges from the classic neonatal type, infantile, intermediate to the atypical adulthood type.6 All these phenotypes are characterized by periods of relative health and intermittent metabolic decompensation, usually associated with infections and stressful events.