Circulating Lymphocytes

from five obligate heterozygotes for type II hyperprolinemia. We also demonstrated a reduction in leukocyte AL-pyrroline-5-carboxylic acid dehydrogenase activity in three successive generations of a family. A portion of this work was presented at the Annual Meeting of The Society for Pediatric Research in Washiilgton, D. C., 3 May 1974, and at the National Meeting of The American Society for Clinical Investigation in Atlantic City, N. J., 3 'May 1975. Received for puiblicationt 12 Decemizber 1975 antd ini revised formii 23 April 1976. These results prove that an absence of A'-pyrroline-5carboxylic acid dehydrogenase is the enzymologic defect in type II hyperprolinemia and that this defect is inherited in an autosomal recessive fashion.