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MCADD

Other Names

Medium chain acyl-CoA dehydrogenase deficiency

ACADM

MCADH

Diagnosis Coding

E71.311, medium chain acyl CoA dehydrogenase deficiency

Disorder Category

A fatty acid oxidation disorder

Screening

Finding

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]

Overview

Medium chain acyl-CoA dehydrogenase deficiency (MCADD) is one of several enzymes involved in the beta-oxidation of fatty acids within mitochondria. MCADD impairs hepatic ketogenesis, resulting in hypoketotic hypoglycemia during periods of prolonged fasting or increased energy demands (e.g., during acute illness or fever).

Incidence

Prevalence is about 1:17,759 live births; it is most common in northern Europeans and US Caucasians. [Therrell: 2014]

Inheritance

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 can appear shortly after birth (sometimes just after hospital discharge) or at time of acute illness, which prevents the child from eating or causes increasing energy expenditure (fever). Some affected individuals do not present until adulthood.

Initial symptoms/signs may include:
  • Poor feeding
  • Vomiting
  • Lethargy progressing to coma
  • Lab findings:
    • Hyperammonemia
    • Hypoglycemia
    • Elevated ALT and AST
Subsequent symptoms/signs may include:
  • Hepatomegaly
  • Liver dysfunction
  • Seizures
  • Encephalopathy
  • Sudden death

Follow-up Testing after Positive Screen

Quantitative plasma acylcarnitine profile, urine acylglycine (increased hexanoylglycine), urine organic acids - diagnosis is confirmed by DNA analysis

Primary Care Management

Upon Notification of the + Screen

  • Contact the family and evaluate the infant for related symptoms.
  • Provide emergency treatment and referral for symptoms of hypoglycemia, lethargy, and feeding problems.
  • Make sure the child eats at regular intervals (every 3 to 4 hours) and formula is available to the family in case breastfeeding becomes insufficient.
  • Confirm the diagnosis, work with the following service(s): Newborn Screening Services (see ID providers [22]).
  • Evaluate and continue ongoing collaborative management, consult the following service(s): Pediatric Genetics (see ID providers [3]).

If the Diagnosis is Confirmed

  • Educate the family about signs, symptoms, the need for frequent feedings, and the need for urgent care if the infant becomes ill. (See MCADD - Information for Parents (STAR-G) for additional information.)
  • Provide an "emergency" letter guiding caregivers in the appropriate response to acute illness and a medical ID bracelet for older kids and adults.
  • Consider a heart-healthy diet for affected children after 1 year of age.
  • Consider oral L-carnitine, which may be recommended in case of deficiency.
  • Assist in management of irreversible consequences as necessary, particularly with developmental and educational interventions.
  • See the Portal’s diagnosis and management module for MCADD.

Specialty Care Collaboration

A dietician may work with the family to devise an optimal approach to dietary management.

Resources

Information & Support

For Professionals

Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency (GeneReviews)
Excellent review of MCADD that includes a clinical description, differential diagnoses, management information, and molecular genetic information; by Detrich Matern, MD and Piero Rinaldo, MD, PhD - sponsored by the U.S. National Library of Medicine.

For Parents and Patients

MCADD - Information for Parents (STAR-G)
A fact sheet, written by a genetic counselor and reviewed by metabolic and genetic specialists, for families who have received an initial diagnosis of this newborn disorder; Screening, Technology and Research in Genetics.

Medium-chain acyl-CoA dehydrogenase deficiency (MedlinePlus)
Information for families that includes description, frequency, causes, inheritance, other names, and additional resources; from the National Library of Medicine.

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

Tools

ACT Sheet for MCAD (ACMG) (PDF Document 348 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

Confirmatory Algorithm for MCADD (ACMG) (PDF Document 63 KB)
Resource for clinicians to help confirm diagnosis; American College of Medical Genetics.

Medium Chain Acyl-CoA Dehydrogenase Deficiency (MCADD) (NECMP) (PDF Document 17 KB)
Guideline for clinicians treating the sick infant or child who has 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.

Services for Patients & Families in Idaho (ID)

Genetics clinic services throughout the US can be found through the Genetics Clinic Services Search Engine (ACMG)

For services not listed above, browse our Services categories or search our database.

* number of provider listings may vary by how states categorize services, whether providers are listed by organization or individual, how services are organized in the state, and other factors; Nationwide (NW) providers are generally limited to web-based services, provider locator services, and organizations that serve children from across the nation.

Helpful Articles

PubMed search for MCADD in children, last 4 years.

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

Authors & Reviewers

Initial publication: March 2007; last update/revision: December 2015
Current Authors and Reviewers:
Author: Nicola Longo, MD, Ph.D.

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

Therrell BL Jr, Lloyd-Puryear MA, Camp KM, Mann MY.
Inborn errors of metabolism identified via newborn screening: Ten-year incidence data and costs of nutritional interventions for research agenda planning.
Mol Genet Metab. 2014;113(1-2):14-26. PubMed abstract / Full Text