Cytogenetic and biochemical studies of the mentally handicapped in Alexandria

ABSTRACT

Seven hundred mentally retarded patients attending the outpatient clinic of the Human Genetics Department, Medical Research Institute were assessed to estimate the frequency of chromosomal anomalies and the biochemical defects. The group included 355 males and 345 females. Chromosomal anomalies were found in 154 patients; numerical autosomal anomalies were detected in 113 patients with trisomy 21 being the most common [107 patients], structural chromosome anomalies were present in 23 patients and sex chromosome anomalies were detected in 4 patients. Fourteen patients were fra [X] +ve constituting 3.9% of the male patients included in this study. Inborn errors of metabolism were detected in 40 patients. Twenty patients had aminoacidopathies; 10 patients had phenylketonuria, 4 had alkaptonuria, 2 had homocystinuria and 4 had generalized aminoacidurias. Twenty patients had lysosomal storage disease; 15 patients had mucopolysaccharidosis, 1 patient had mucolipidosis and 4 patients had sphingolipidosis