A genetic diagnostic survey in an institutionalized population of 116 moderately to severely retarded male patients: the Rekem experience.

In this paper we report the results of a genetic-diagnostic survey of 116 institutionalized male patients who were moderately to severely retarded. In 31 patients (26.7%) a constitutional cause of their mental impairment was found: chromosomal abnormalities in 11 patients (9.5%), Mendelian disorders in 16 (13.8%), of which 8 fragile X patients (6.9%), and a MCA/MR syndrome in 4 patients (3.4%). Acquired forms of mental retardation occurred in 26 patients (22.4%): CNS-dysfunction due to pre-, peri- or postnatal causes were most likely in 18 patients (15.5%), while infections played a major role in 8 (6.9%). In 59 patients (50.9%) not etiological diagnosis could be made.