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Abstract:

Three disorders of proline metabolism are known: two in its catabolism (hyperprolinemia type I due to proline oxidase deficiency and hyperprolinemia type II due to Δ1-pyrroline 5-carboxylate dehydrogenase deficiency) and one in its synthesis (Δ1-pyrroline 5-carboxylate synthase deficiency). Hyperprolinemia type I is mostly considered a non-disease, while hyperprolinemia type II seems to be associated with a disposition to recurrent seizures. The deficiency of the proline-synthesizing enzyme, Δ1-pyrroline 5-carboxylate synthase, which also intervenes in ornithine synthesis, is described in ▶ Chap. 22. Three disorders of serine metabolism are known. Two are in its biosynthesis: namely, 3-phosphoglycerate dehydrogenase deficiency and phosphoserine phosphatase deficiency. Patients with 3-phosphoglycerate dehydrogenase deficiency are affected with congenital microcephaly, psychomotor retardation and intractable seizures and partially respond to L-serine or L-serine and glycine. One patient with an association of Williams syndrome and phosphoserine phosphatase deficiency has been reported. Another, unexplained serine disorder has been reported in a patient with decreased serine in body fluids, ichthyosis and polyneuropathy but no central nervous system manifestations. There was a spectacular response to L-serine. © 2006 Springer Medizin Verlag Heidelberg.