Hyperlysinemia with saccharopinuria due to combined lysine-ketoglutarate reductase and saccharopine dehydrogenase deficiencies presenting as cystinuria.
A 7-year-old boy with speech delay, hyperactive behavior, and minor neurologic abnormalities had been found in the past to have "intermittent cystinuria." A more detailed investigation revealed hyperlysinemia and hyperlysinuria, with lesser increases in urinary excretion of arginine and cystine. The plasma and urine abnormalities increased on a diet of 3 gm of protein/kg body weight/day. Saccharopine, a normal metabolite of lysine not found in the body fluids of normal people, was present in plasma, cerebrospinal fluid, and urine of the patient. Lysine-ketoglutarate reductase and saccharopine dehydrogenase activities were not detectable in extracts of cultured skin fibroblasts. Re-examination of the urine of previously studied cases of this double enzyme deficiency suggests that saccharopinuria of variable degree is the rule and not the exception.
D002478:Cells, Cultured; D002648:Child; D003555:Cystinuria / Q000175:diagnosis; D003677:Deficiency Diseases / Q000150:complications; D003937:Diagnosis, Differential; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D007655:Ketoglutarate Dehydrogenase Complex / Q000172:deficiency*; D007658:Ketone Oxidoreductases / Q000172:deficiency*; D008239:Lysine / Q000031:analogs & derivatives* / Q000097:blood* / Q000378:metabolism / Q000652:urine*; D008297:Male; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000172:deficiency*; D000608:Renal Aminoacidurias / Q000175:diagnosis; D012443:Saccharopine Dehydrogenases / Q000172:deficiency*; D012867:Skin / Q000648:ultrastructure
D007658:Ketone Oxidoreductases; D007655:Ketoglutarate Dehydrogenase Complex; D000587:Oxidoreductases Acting on CH-NH Group Donors; D012443:Saccharopine Dehydrogenases; D008239:Lysine