Prolidase deficiency with imidodipeptiduria. A familial case with and without clinical symptoms

A 23-year-old female with chronic leg ulcer was found to excrete the massive imidopeptides, among which Asp-Pro, Glu-Pro and Gly-Pro were identified. Essentially no prolidase activity was measured in her erythrocytes, while prolinase activity was within a normal range. Her 26-year-old brother also showed imidopeptiduria and erythrocyte prolidase deficiency, but no clinical symptoms were observed. Erythrocytes from her father and 30-year-old brother, who excreted no significant amounts of imidodipeptides, showed intermediate values for the prolidase activity between those for the patient and for normal adults, suggesting that they are heterozygous for this autosomal recessive disorder.