Medium-chain acyl-CoA dehydrogenase deficiency
Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is a metabolic disorder that prevents the body from converting certain fats into energy, particularly during fasting.
Overview
MCAD deficiency is a condition that impairs the body's ability to break down medium-chain fatty acids. Symptoms typically appear during infancy or early childhood, though some cases are not diagnosed until adulthood. If left unmanaged, the condition can lead to life-threatening complications.
Symptoms
Symptoms are often triggered by fasting or viral illnesses and include:
- Vomiting and lack of energy (lethargy).
- Low blood glucose (hypoglycemia).
- Seizures and breathing difficulties.
- Liver problems and potential brain damage.
- Coma or sudden death in severe, untreated cases.
The disorder is sometimes mistaken for Reye syndrome, a severe condition that can occur during recovery from viral infections.
Causes
The condition is caused by mutations in the ACADM gene. This gene provides instructions for creating the MCAD enzyme, which is required to metabolize medium-chain fatty acids. These fatty acids are a vital energy source for the heart, muscles, and liver, especially during periods without food.
When the MCAD enzyme is deficient:
- The body cannot convert fats into necessary energy.
- Medium-chain fatty acids or partially metabolized fats build up in tissues.
- This accumulation can damage the liver and brain, leading to the symptoms of the disorder.
Inheritance
MCAD deficiency is inherited in an autosomal recessive pattern. This means that both copies of the ACADM gene in each cell must have mutations for the condition to occur. Parents of an affected individual each carry one mutated copy of the gene but typically do not exhibit symptoms themselves.