Disorder Category

a fatty acid oxidation disorder



elevated C14:1 +/- (acylcarnitine)

Tested By

tandem mass spectrometry (MS/MS); sensitivity and specificity unknown [Ficicioglu: 2010]



Very long chain acyl-CoA dehydrogenase deficiency

ACADVL deficiency


277.85, Disorders of fatty acid oxidation


During prolonged fasting and/or periods of increased energy demands (fever, stress, lack of sleep) energy production relies increasingly on fat metabolism. VLCAD enzyme deficiency (an intramitochondrial defect in the beta-oxidation of fatty acids) impairs this form of energy production, causing metabolic crisis, cardiomyopathy, muscle pain, or myoglobinuria. Variants exist including "Early," "Childhood," and "Adult". Sudden infant deaths may occur as a result of cardiac abnormalities.


autosomal recessive

Maternal and Family History

There may be a family history of Sudden Infant Death Syndrome (SIDS).

Prenatal Testing

DNA testing or enzyme analysis by amniocentesis or CVS.

Clinical Characteristics

With treatment, risk of sudden death appears to be reduced. Without treatment, sudden cardiac death is common in the early childhood form. Symptoms of the "early" type may begin between birth and four months of age while the "childhood" type may begin in later infancy or early childhood especially after fasting or illness. The "adult" type may begin in adolescence or adulthood and may be triggered by prolonged exercise. Symptoms may be mild or severe.

Initial signs/symptoms in the "early" and "childhood" types may include:
  • poor feeding,
  • vomiting,
  • diarrhea,
  • irritability,
  • behavior changes,
  • extreme sleepiness,
  • muscle weakness,
  • lethargy, and
  • lab findings:
    • metabolic acidosis, and
    • hypoglycemia.

If not treated promptly, patients may experience:
  • heatomegaly,
  • difficulty breathing,
  • muscle weakness with exertion,
  • arrhythmia,
  • cardiomyopathy,
  • seizures,
  • brain damage, and
  • death.

"Adult" type symptoms may include:
  • muscle breakdown,
  • muscle aches,
  • weakness,
  • cramps,
  • reddish-brown urine, and
  • kidney failure.

Follow-up on positive screening test

Quantitative plasma acylcarnitine profile, mutation analysis of the VLCAD gene, enzyme assay in fibroblasts, and additional biochemical genetic tests.

Primary care management

Upon notification of the + screen

  • contact the family and evaluate the infant for poor feeding, lethargy, hypotonia, hepatomegaly, or cardiac problems;
  • Provide emergency treatment/referral for symptoms of hypoglycemia, arrhythmia, or cardiac decompensation;
  • To confirm the diagnosis, work with the following service(s): see all Newborn Screening Programs services providers (1) in our database;
  • For evaluation and ongoing collaborative management, consult the following service(s): Pediatric Medical Genetics, (801-213-3599); See also Services below;

If the diagnosis is confirmed

  • Educate the family regarding signs, symptoms, and the need for urgent care when the infant becomes ill (see VLCADD info for parents (STAR-G) for additional information);
  • Assist with implementation of a low-fat, high carbohydrate diet;
  • Oral L-carnitine and medium chain triglyceride (MCT) oil supplements may be indicated;
  • Cornstarch supplements and avoidance of long chain fatty acids may also be indicated;
  • For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions.

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 VLCADD Diagnosis Module.


Information & Support

For Professionals

VLCADD 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 VLCADD (ACMG) (PDF Document 347 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.

VLCADD Acute Illness Protocol (NECMP)
A guideline for healthcare professionals treating the sick infant/child who has previously been diagnosed with VLCADD; 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.

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

Extensive review of the literature, including clinical features and genetics, from the Online Mendelian Inheritance in Man site, hosted by Johns Hopkins University, providing technical information for providers on genetic disorders, links to MEDLINE, and links to other scientific information and sites.

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

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

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

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


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.


Reviewing Author: Nicola Longo, MD, PhD - 3/2007
Compiled and edited by: Alfred Romeo, RN, PhD - 3/2007
Content Last Updated: 1/2011

Page Bibliography

Ficicioglu C, Coughlin CR 2nd, Bennett MJ, Yudkoff M.
Very long-chain acyl-CoA dehydrogenase deficiency in a patient with normal newborn screening by tandem mass spectrometry.
J Pediatr. 2010;156(3):492-4. PubMed abstract