Prolidase deficiency is a disorder that causes a wide variety of symptoms. The disorder typically becomes apparent during infancy. Affected individuals may have enlargement of the spleen (splenomegaly); in some cases, both the spleen and liver are enlarged (hepatosplenomegaly). Diarrhea, vomiting, and dehydration may also occur. People with prolidase deficiency are susceptible to severe infections of the skin or ears, or potentially life-threatening respiratory tract infections. Some individuals with prolidase deficiency have chronic lung disease.

Prolidase deficiency is caused by mutations in the PEPD gene. This gene provides instructions for making the enzyme prolidase, also called peptidase D. Prolidase helps divide certain dipeptides, which are molecules composed of two protein building blocks (amino acids). Specifically, prolidase divides dipeptides containing the amino acids proline or hydroxyproline. By freeing these amino acids, prolidase helps make them available for use in producing proteins that the body needs.

Prolidase deficiency is a rare disorder. Approximately 70 individuals with this disorder have been documented in the medical literature, and researchers have estimated that the condition occurs in approximately 1 in 1 million to 1 in 2 million newborns. It is more common in certain areas in northern Israel, both among members of a religious minority called the Druze and in nearby Arab Moslem populations.

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.

Published Date: February 01, 2012
Published By: National Institutes of Health