Hyperprolinemia type II. Pyrroline-5-carboxylate dehydrogenase deficiency.
Incidence
Autosomal recessive. Rare condition.
Clinical Characteristics
In hyperprolinemia type II, which is usually characterized by mental retardation and convulsions, the enzyme defect involves pyrroline-5-carboxylate dehydrogenase and the substance normally acted on by this enzyme, P5C or pyrroline-5-carboxylate, is excreted in the urine. Emery et al (1968) described an affected mentally retarded 18-year-old girl whose retarded sister had died, presumably of the same disorder. Selkoe (1969) described a second type of hyperprolinemia with only mild mental retardation and without renal disease. Pavone et al. (1975) described 3 clinically normal sibs with type II hyperprolinemia. They lived in eastern Sicily and had first-cousin parents. All 3 also showed hyperglycinemia. The association is unexplained. No relation between proline and glycine metabolism is evident. Valle et al. (1979) found that both proline oxidase and hydroxyproline oxidase are deficient in hyperprolinemia type II.
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
EB-W. EB-F. Delta-1-pyrroline-5-carboxylate dehydrogenase activity decreased in fibroblasts or leukocytes. Aminoacids in plasma and urine quantitative.