Malonyl-coenzyme A decarboxylase deficiency

Malonyl-coenzyme A (CoA) decarboxylase deficiency is a condition that prevents the body from converting certain fats to energy. The signs and symptoms of this disorder typically appear in early childhood. Almost all affected children have delayed development. Additional signs and symptoms can include weak muscle tone (hypotonia), seizures, diarrhea, vomiting, and low blood sugar (hypoglycemia). A heart condition called cardiomyopathy, which weakens and enlarges the heart muscle, is another common feature of malonyl-CoA decarboxylase deficiency.

This condition is very rare; fewer than 20 cases have been reported.

Mutations in the MLYCD gene cause malonyl-coenzyme A decarboxylase deficiency.

The MLYCD gene provides instructions for making an enzyme called malonyl-CoA decarboxylase. Within cells, this enzyme helps regulate the formation and breakdown of a certain group of fats called fatty acids. Many tissues, including heart muscle, use fatty acids as a major source of energy. Mutations in the MLYCD gene reduce or eliminate the function of malonyl-CoA decarboxylase. A lack of this enzyme disrupts the normal balance of fatty acid formation and breakdown. As a result, fatty acids cannot be converted to energy, which can lead to characteristic features of this disorder such as low blood sugar and cardiomyopathy. Byproducts of fatty acid processing build up in tissues, which also contributes to the signs and symptoms of malonyl-CoA decarboxylase deficiency.

Read more about the MLYCD gene.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.