Acyl-coa dehydrogenase, medium-chain, deficiency of

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is caused by alterations (mutations) in the ACADM gene. Our genes contain our body's genetic information, called DNA; genes are segments of DNA found on chromosomes. Genes are inherited from our parents and passed on to our children. Genes are like our body's instruction manual - they control the growth, development and normal function of the body. Genes produce specific proteins that the body needs to grow and work properly. When there is an unexpected change in a gene, the protein that the gene produces may be absent or not work properly or be overproduced.

In MCAD deficiency, an alteration in the ACADM gene leads to a deficiency of the enzyme, medium-chain acyl-CoA dehydrogenase or MCAD. This enzyme is required to break down (metabolize) fats in the body.

Normally, the body uses a sugar called glucose for energy. When people do not eat for period of time and/or experience higher energy demands the glucose in the body may be used up. 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. People with MCAD deficiency will be very sleepy or sluggish during an episode because the body cannot produce the energy it needs.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is caused by a change (variant) in the ACADM gene. Not all changes in a gene necessarily cause disease. If a change is known to cause MCAD deficiency, it is known as a pathogenic or disease-causing variant. Specific changes in the ACADM gene(s) can cause MCAD deficiency. However, sometimes gene changes are found and scientists are unsure what it means, either because it has not been found before or has only been found in a few people. This is known as a variant of unknown significance. If you have a variant of unknown significance in the ACADM gene(s), talk to your doctor about further testing that may help find out whether the gene change is pathogenic or not. A genetic counselor may also be able to help you review your test results. Genetic counselors can be found on the National Society of Genetic Counselors website.