Biochemical screening for certain inborn errors of metabolism that cause mental retardation in Egyptian children

ABSTRACT

Among 1268 patients with genetic diseases referred of the human Genetics Department [NRC]. 197 cases [15.5%] had isolated mental retardation. The present study deals with biochemical screening of certain metabolic abnormalities in these 197 cases. Biochemical screening was by qualitative chemical tests on urine for the detection of certain defects in amino acid. Carbohydrate and mucopolysaccharide metabolism and by thin layer chromatographic detection of specific amino acids in plasma and urine. Quantitative determinations of urea, creatinine, ammonia and uric acid in plasma, argininosuccinase and arginase enzyme activities in erythrocytes; mucopolysacchrides and creatinine in urine were done when indicated. Our results indicated that 83 patienls of the 197 [42.13%] had inborn errors of metabolism 77.1%, of them had amino acidopathies and urea cycle disorders and 22.9% had mucopolysacharidosis. Parental consanguity rate was high [61%]. From the results of this investigation we recommend the need to avoid consanguineous marriages in our society and to initiate neonatal screening programs for early detection and treatment of these defects whenever possible and for proper genetic counseling and prenatal diagnosis in subsequent pregnancies