[Screening for congenital metabolic diseases in mentally retarded patients in 6 psychiatric institutions of Lower Saxony].

The results of screening for inborn errors of metabolism in patients in six institutions for the mentally retarded in Lower Saxony are presented. A battery of standard chemical and chromatographic tests for amino acids, carbohydrates and mucopolysaccharides in urine were employed. Combined gas chromatography-mass spectrometry was used to detect organic aciduria. All together 975 patients - 347 females and 628 males - aged from 5 to 93 years were studied. 78.6% of the patients were over 20 years of age. There were positive findings in 56 cases: phenylketonuria (n = 8), alcaptonuria (1), pentosuria (5), galactosuria (2), tryptophanuria (1), xanthurenic aciduria (3), mucopolysaccharidosis type III A (1), hyperglycinemia with hyperglycinuria (1), renal hyperaminoaciduria (9, lactic aciduria (3), 4-hydroxyphenylaceticaciduria (2), organic aciduria (12) and mellituria (8) of unknown type. The organic acids most often detected in urine were lactic, 4-hydroxyphenylacetic and 3-hydroxybutyric acids. Only 20 of the patients (2.0%) excreted appreciable amounts of benzoic acid in urine. The results are discussed and compared with other investigations.