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GTR Home > Conditions/Phenotypes > Medium-chain acyl-coenzyme A dehydrogenase deficiency


Excerpted from the GeneReview: Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency
Medium-chain acyl-coenzyme A dehydrogenase (MCAD) is one of the enzymes involved in mitochondrial fatty acid β-oxidation. Fatty acid β-oxidation fuels hepatic ketogenesis, which provides a major source of energy once hepatic glycogen stores become depleted during prolonged fasting and periods of higher energy demands. MCAD deficiency is the most common disorder of fatty acid β-oxidation and one of the most common inborn errors of metabolism. Most children are now diagnosed through newborn screening. Clinical symptoms in a previously apparently healthy child with MCAD deficiency include hypoketotic hypoglycemia and vomiting that may progress to lethargy, seizures, and coma triggered by a common illness. Hepatomegaly and liver disease are often present during an acute episode. Children appear normal at birth and – if not identified through newborn screening – typically present between age three and 24 months, although presentation even as late as adulthood is possible. The prognosis is excellent once the diagnosis is established and frequent feedings are instituted to avoid any prolonged periods of fasting.

Genes See tests for all associated and related genes

  • Also known as: ACAD1, MCAD, MCADH, ACADM
    Summary: acyl-CoA dehydrogenase medium chain

Clinical features


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Practice guidelines

  • ACMG ACT, 2021
    American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Elevated C8 with Lesser Elevations of C6 and C10 Acylcarnitine, Medium-Chain Acyl-CoA Dehydrogenase (MCAD) Deficiency, 2021
  • ACMG Algorithm, 2021
    American College of Medical Genetics and Genomics, Algorithm, C8 Elevated + Lesser Elevations of C6 and C10, 2021

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