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)
Structured list of information about the condition, with links to more information; Screening, Technology, and Research in Genetics.

ACT Sheet for MCADD (ACMG) (PDF Document 348 KB)
Recommended responses to positive newborn screening test results. Includes diagnostic evaluation, clinical expectations, and sources of additional information; American College of Medical Genetics.

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)
Guideline for clinicians 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. Click pdf to view the complete protocol.

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; sponsored by the U.S. National Library of Medicine.

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 (AAP)
The goal of this site is to increase 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)
Information for parents about MCADD, support groups, and links to other sites; Screening, Technology and Research in Genetics.

MCADD (Genetics Home Reference)
Detailed review aimed at patients and families; sponsored by the National Library of Medicine.

MCADD: A Guide for Parents (PacNoRGG) (PDF Document 618 KB)
Eight-page guide that includes an overview, social concerns, sample treatment plan, glossary, regional resources, and references; sponsored by the Pacific Northwest Regional Genetics Group.

MCADD: A Guide for Parents (PacNoRGG) (Spanish) (PDF Document 202 KB)
Spanish translation of an 8-page guide that includes an overview, social concerns, sample treatment plan, glossary, regional resources, and references; sponsored by the Pacific Northwest Regional Genetics Group.

Fatty Oxidation Disorders (FOD) Family Support Group
Information for families about fatty acid oxidation disorders, support groups, coping, finances, and links to other sites.

National Newborn Screening & Genetics Resource Center (NNSGRC)
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 (1) in our database.

Pediatric Genetics

See all Pediatric Genetics services providers (3) in our database.

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

Helpful Articles

PubMed search for MCADD in children, last 3 years.

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