medium chain acyl-CoA dehydrogenase deficiency

What is Medium Chain Acyl-CoA Dehydrogenase Deficiency?

Medium chain acyl-CoA dehydrogenase (MCAD) deficiency is a treatable inherited disease in which the body cannot turn certain fatty acids into energy due to a deficient enzyme. As a result, partially metabolized fatty acids can accumulate in body tissues, causing damage to the brain, liver, and other organs. If treated early and consistently, people with MCAD deficiency can live normal lives.

Children with untreated MCAD deficiency are prone to quick-developing, life-threatening health problems including seizures, breathing problems, brain damage, coma, and death. The liver may also be enlarged. It is thought that a small percentage of sudden infant death syndrome is due to undiagnosed MCAD deficiency.

The first symptoms of the disease usually appear in infancy or early childhood. These include vomiting, lack of energy, and low blood sugar. Rarely, these symptoms do not appear until adulthood. Often the episodes of metabolic crisis can be triggered by long periods without eating or by illness.

Women whose fetuses have MCAD deficiency are more prone to certain pregnancy complications and should speak with their physician.

How common is Medium Chain Acyl-CoA Dehydrogenase Deficiency?

MCAD deficiency is most common in Caucasians from Northern Europe. In the United States, the disease affects approximately 1 in 17,000 people. Affected Americans are often of Northern European ancestry. The disease is rare among Hispanics, African Americans, Asians, and Native Americans in the United States.

Studies have found high rates of MCAD deficiency in Northern Germany (1 in 4,900) and Southern Germany (1 in 8,500). One study found that Germans and Turks are equally affected.

How is Medium Chain Acyl-CoA Dehydrogenase Deficiency treated?

The key to treatment for people with MCAD deficiency is to avoid fasting, or long periods without eating. Infants will need to be fed frequently with a special diet low in fat. Consuming cornstarch can provide a sustained release of energy and allow for longer gaps between meals. Certain types of fat should be avoided while high amounts of carbohydrates can be beneficial. If the person is unable to consume food, intravenous glucose may be necessary. People with MCAD deficiency should speak with their medical team to devise a specialized diet.

What is the prognosis for a person with Medium Chain Acyl-CoA Dehydrogenase Deficiency?

If a person affected by MCAD deficiency is diagnosed early and treated promptly, the prognosis is good. He or she can lead a normal or near-normal life.

Because the metabolic crises caused by the disease can quickly progress from first symptom to death, it is possible for people who remain undiagnosed to die during their first episode.