Acyl-coa dehydrogenase, medium-chain, deficiency of
What are the first steps after a newborn screening test is positive for medium-chain acyl-CoA dehydrogenase deficiency (MCAD)?
If an infant has a positive newborn screening test for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, then further testing will be done to confirm that the child has the disorder. If the diagnosis is confirmed, families should seek a medical consultation with a physician such as a metabolic genetic specialist with experience in treating the disorder. Treatment requires that parents make sure that their infants or children do not go long periods of time without eating. Other initial steps will depend on how the disorder is affecting a person and whether the disorder was diagnosed after an episode of metabolic crisis. Families should see a genetic counselor to help understand the genetic aspects of this disorder. Genetic counselors can be found on the National Society of Genetic Counselors website.
Families may consider contacting a support group after a diagnosis of MCAD deficiency. The FOD Family Support Group provides information, support, guidance, referrals and networking among other programs for individuals and families affected by fatty oxidation disorders like MCAD deficiency.
- Newborn Screening ACT Sheet: Elevated C8 with Lesser Elevations of C6 and C10 Acylcarnitine (Medium-chain Acyl-CoA Dehydrogenase (MCAD) Deficiency. American College of Medical Genetics website. http://www.acmg.net/StaticContent/ACT/C8_C6_C10.pdf
- Medium-Chain Acyl-CoA Dehydrogenase Deficiency. Baby's First Test website. http://www.babysfirsttest.org/newborn-screening/conditions/medium-chain-acyl-coa-dehydrogenase-deficiency
More Treatment Content
Is there a treatment for medium-chain acyl-CoA dehydrogenase deficiency (MCAD)?
The main treatment for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is avoiding having children or adults with this disorder go long periods of time without eating. When the body lacks glucose, it will instead use fats for energy. The MCAD enzyme is needed to break down fats, specifically medium-chain fatty acids, for energy. These fatty acids are primarily obtained from food. Since affected people lack the MCAD enzyme, they cannot break down these fatty acids, which build up in the body. This buildup of fats inhibits or affects other chemical processes in the body.
There are guidelines that explain what doctors believe are the safe time gaps for people with MCAD deficiency. Infants require frequent feedings and they should not be given formula that contains medium-chain fatty acids. Toddlers can be given cornstarch before bed to make sure that they have enough glucose to last through the night. Some medical sources suggest that a low-fat diet (less than 30% of energy from fat) may be beneficial.
Some doctors suggest that all people with MCAD deficiency should follow a low-fat diet, or avoid a high-fat diet. But not all doctors feel that this is necessary. When people with MCAD deficiency are at risk of a metabolic episode, like during an illness or when they have not eaten for a long time, then glucose supplementation is recommended. This can be achieved through drinking orange juice or non-diet drinks. Glucose tablets can also be used.
Some people with MCAD deficiency have low carnitine levels. Carnitine is a substance made by the body that helps to carries waste from the body. People with MCAD deficiency may have more waste products and consequently may need to use more carnitine. If people with this disorder have low carnitine levels then some doctors may prescribe a carnitine supplement.
Many physicians and many emergency personnel will not be familiar with the disorder. People with MCAD deficiency should carry an emergency letter that explains MCAD deficiency and the appropriate management or treatment of a metabolic crisis. Metabolic crisis in MCAD deficiency occurs when people with the disorder do not eat for a period of time or experience higher energy demands for the body. The time gap is defined as 8 hours for infants between 6 months and 12 months of age, up to 10 hours for children age 2 and up, to 12 hours for children over 2 years of age (this applies to teenagers and adults as well). The letter should also explain the importance of preventive steps to take. The letter should also have the names and contact information of the patient's doctors and metabolic specialists.
- Matern D, Rinaldo P. Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency. GeneReviews website. https://www.ncbi.nlm.nih.gov/books/NBK1424/#mcad
- Medium Chain Acyl CoA Dehydrogenase Deficiency. The National Organization for Rare Disorders website. https://rarediseases.org/rare-diseases/medium-chain-acyl-coa-dehydrogenase-deficiency
- Gartner V, McGuire PJ, Lee PR. Child Neurology: Medium-chain acyl-coenzyme A dehydrogenase deficiency. Neurology. 2015;85(4):e37-e40.
- Medium chain acyl-CoA dehydrogenase deficiency. OrphaNet website. http://www.orpha.net/consor/cgi-bin/Disease_Search.php?lng=EN&data_id=3570
- Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency" Genetics Home Reference website. https://ghr.nlm.nih.gov/condition/medium-chain-acyl-coa-dehydrogenase-deficiency
- Roe CR. MCAD: Medium Chain acyl CoA Dehydrogenase - Information for Families. The FOD Family Support Group website. https://fodsupport.org/description