Clinical and biochemical characteristics of prolidase deficiency in siblings.

Two brothers with recurrent skin ulcers of the lower limbs, subnormal intelligence, developmental abnormalities, and poliosis were found to excrete large quantities of several imidodipeptides in their urine. Glycylproline was the most prominent imidodipeptide excreted and was also detected in their blood. Prolidase activity was markedly deficient in red blood cells from both patients (4.1% and 3.7% of control mean) and skin fibroblasts from the one brother so examined (3.7% of control mean). A total of 20 patients with prolidase deficiency, including the two in this report, have been described in the literature. Their manifestations and various attempts at treatment are reviewed.