Hg blocking Coenzym A 1

Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency

Synonym: MCAD Deficiency

Dietrich Matern, MD and Piero Rinaldo, MD, PhD.

Initial Posting: April 20, 2000; Last Update: January 19, 2012.


Disease characteristics. Medium-chain acyl-coenzyme A dehydrogenase (MCAD) is one of the enzymes involved in mitochondrial fatty acid β-oxidation, which fuels hepatic ketogenesis, a major source of energy once hepatic glycogen stores become depleted during prolonged fasting and periods of higher energy demands. In a typical clinical scenario, a previously healthy child with MCAD deficiency presents with hypoketotic hypoglycemia, vomiting, and lethargy triggered by a common illness. Seizures may occur. Hepatomegaly and liver disease are often present during an acute episode, which can quickly progress to coma and death. Children are normal at birth and – if not identified through newborn screening – typically present between ages three and 24 months; later presentation, even into adulthood, is possible. The prognosis is excellent once the diagnosis is established and frequent feedings are instituted to avoid any prolonged period of fasting.