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Disorder Category

a fatty acid oxidation disorder



elevated C8 (octanoylcarnitine) with lesser elevations of C6 (hexanoylglycine) and C10:1 (decenoyl carnitine)

Tested By

tandem mass spectrometry (MS/MS); sensitivity=100%; specificity=99.98% [Schulze: 2003]



Medium chain acyl-CoA dehydrogenase deficiency (MCAD, MCADD)




277.85, Disorders of fatty acid oxidation


MCADD is one of several enzymes involved in the beta-oxidation of fatty acids within mitochondria. MCAD deficiency impairs hepatic ketogenesis, resulting in hypoketotic hypoglycemia during prolonged fasting and/or periods of increased energy demands (acute illness, fever).


about 1/15,600 live births; [Schulze: 2003] most common in Northern Europeans and US Caucasians


autosomal recessive

Prenatal Testing

Amniocentesis or chorionic villous sampling (CVS) for DNA testing

Clinical Characteristics

With treatment, prognosis is excellent. Without treatment, episodes of hypoketotic hypoglycemic, accompanied by lethargy and vomiting, may lead to seizures, coma, cardiac arrest, and death. Symptoms typically begin between birth and 2 years of age, though some affected individuals do not present till adulthood.

Initial symptoms/signs may include:
  • poor feeding,
  • vomiting,
  • lethargy progressing to coma,
  • lab findings:
    • hyperammonemia, and
    • hypoglycemia.

Subsequent symptoms/signs may include:
  • hepatomegaly,
  • liver dysfunction,
  • seizures,
  • encephalopathy, and
  • sudden death.

Follow-up on positive screening test

Quantitative plasma acylcarnitine profile, urine acylglycine (increased hexanonylglycine), urine organic acids. Diagnosis is confirmed by DNA analysis.

Primary care management

Upon notification of the + screen

If the diagnosis is confirmed

  • Educate the family regarding signs, symptoms, the need for frequent feedings, and the need for urgent care when the infant becomes ill (see MCADD info for parents (STAR-G) for additional information); provide an "emergency" letter guiding caregivers in the appropriate response to acute illness (and an MedicAlert bracelet for older kids and adults)
  • Frequent, low fat, high carbohydrate meals and snacks may be indicated for affected children
  • Glucose may be indicated during hypoglycemic episodes
  • Oral L-carnitine may be recommended for some children
  • For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions
  • See also the Diagnosis Module on MCADD

Specialty Care Collaboration

Initial consultation and ongoing collaboration if the child is affected. A dietician may work with the family to devise an optimal approach to dietary management.

See also the MCADD Diagnosis Module.


Information & Support

For Professionals

MCADD info for professionals (STAR-G)
On the Screening, Technology and Research in Genetics (STAR-G) site, one of a series of Disorder Fact Sheets for Professionals; structured list of information about the condition, with links to more information.

ACT Sheet for MCADD (ACMG)(PDF Document 348 KB)
Developed by the American College of Medical Genetics (ACMG), includes recommended responses to positive newborn screening test results, diagnostic evaluation, clinical expectations, and sources of additional information. See the ACMG ACT Sheets and Confirmatory Algorithms (link elsewhere on this page) for more info and sheets on other conditions.

Newborn Screening ACT Sheets & Confirmatory Algorithms (ACMG)
ACTion (ACT) Sheets and algorithms for responding to positive newborn screening test results, membership required; American College of Medical Genetics.

MCADD Acute Illness Protocol (NECMP)(PDF Document 17 KB)
A guideline for healthcare professionals treating the sick infant/child who has previously been diagnosed with MCADD; developed under the direction of Dr. Harvey Levy, Senior Associate in Medicine/Genetics at Children’s Hospital Boston, and Professor of Pediatrics at Harvard Medical School, for the New England Consortium of Metabolic Programs.

MCADD (GeneReviews)
Excellent review by Detrich Matern, MD and Piero Rinaldo, MD, PhD including clinical description, differential, management, genetic counseling, molecular genetics, and a bibliography.

Resource for MCADD (NLM)
Comprehensive compilation of links to information, articles, research, case studies, genetics, and more; from the National Library of Medicine and the Genetic Alliance.

Genetics in Primary Care Institute (GPCI)
Increases collaboration in the care of children with known or suspected genetic disorders. Includes health supervision and management guidelines, and other useful resources; a collaboration among the Health Resources & Services Administration, the Maternal & Child Health Bureau, and the American Academy of Pediatrics.

For Parents and Patients

MCADD info for parents (STAR-G)
From the Screening, Technology and Research in Genetics (STAR-G) site, providing information for parents about MCADD and links to other sites including parent support groups.

MCADD (Genetics Home Reference)
Excellent, detailed review aimed at patients and families from the National Library of Medicine's Genetics Home Reference site.

MCAD: A Guide for Parents(PDF Document 618 KB)
From the Western States Genetic Services Collaborative, this 8-page guide provides information about Medium Chain Acyl-CoA Dehydrogenase Deficiency including an overview; social concerns; sample treatment plan; glossary; regional resources; references and more.

MCAD: A Guide for Parents (Spanish)(PDF Document 202 KB)
Spanish translation of an 8-page guide provides information about Medium Chain Acyl-CoA Dehydrogenase Deficiency including an overview; social concerns; sample treatment plan; glossary; regional resources; references and more; from the Western States Genetic Services Collaborative.

Fatty Oxidation Disorders (FOD) Family Support Group
The FODsupport.org site offers a variety of information for families about fatty acid oxidation disorders, support groups, coping, finances, and links to other sites.

National Newborn Screening & Genetics Resource Center
Provides information for families and professionals about genetic screening; links to support and advocacy groups; links to state genetic contacts; newsletters; fact sheets; data reports; publications; and more.


Genetics-related clinical services throughout the world can be found through Genetics Clinic Directory (GeneTests).

Newborn Screening Programs

See all Newborn Screening Programs services providers (3) in our database.

Pediatric Genetics

See all Pediatric Genetics services providers (2) in our database.

For other services related to this condition, browse our Services categories or search our database.

Helpful Articles

PubMed search on Neonatal Screening for MCADD

Leonard JV, Dezateux C.
Newborn screening for medium chain acyl CoA dehydrogenase deficiency.
Arch Dis Child. 2009;94(3):235-8. PubMed abstract


Author: Nicola Longo, MD, PhD - 3/2007
Compiled and edited by: Alfred Romeo, RN, PhD - 3/2007
Content Last Updated: 7/2010

Page Bibliography

Schulze A, Lindner M, Kohlmuller D, Olgemoller K, Mayatepek E, Hoffmann GF.
Expanded newborn screening for inborn errors of metabolism by electrospray ionization-tandem mass spectrometry: results, outcome, and implications.
Pediatrics. 2003;111(6 Pt 1):1399-406. PubMed abstract