[Methylmalonic acidemia: classification, diagnosis and therapy]

Methylmalonic acidemia is a recessively inherited inborn error of metabolism presenting with metabolic acidosis, vomiting, lethargy, anorexia, and hypotonia. The disease may either begin in the neonatal period with acute, life-threatening episodes, or manifest itself with a milder clinical course and a more favorable outcome depending on the location and the severity of enzyme block. Enzymatic abnormalities, clinical features, diagnostic approach with regard to differential diagnosis and the possible treatment are discussed. Genetic counseling and prenatal diagnosis are also stressed.