Prolidase deficiency

Prolidase deficiency is a rare autosomal recessive inborn error of metabolism.

Although metabolism of the amino acid proline is affected by the enzyme prolidase, this disorder is not to be confused with hyperprolinemia, which involves different enzymatyic pathways related to proline metabolism.

Characteristics
Prolidase deficiency is characterized by severe skin ulcers, facial abnormalities, chronic joint dislocations, bacterial infections, and mental retardation. Asymptomatic individuals with the disorder, though rare, have also been recognized. . Due to this deficiency of the exopeptidase called prolidase, affected individuals may also excrete large amounts of iminodipeptides in the urine, a condition called iminodipeptiduria.

Cause and genetics
Mutations in the PEPD gene on chromosome 19q13.11 have been observed to cause prolidase deficiency. The disorder is inherited in an autosomal recessive manner. This means the defective gene responsible for the disorder is located on an autosome (chromosome 19 is an autosome), and two copies of the defective gene (one inherited from each parent) are required in order to be born with the disorder. The parents of an individual with an autosomal recessive disorder both carry one copy of the defective gene, but usually do not experience any signs or symptoms of the disorder.