Prominent satellites in oligophrenic, malformed patients: incidence, frequency of satellite associations and karyotype-phenotype comparisons

Abstract

Lymphocyte chromosome preparations from 51 malformed patients with idiopathic mental retardation were analyzed for presence or absence of prominent satellites, a high frequency (22%) of s+ variants being found. However, it is not possible to visualize a phenotypic tendency in the s+ patients either as an increase or decrease in IQ levels or as an etiological relation of the quantitative or qualitative developmental disorders. G--and Ag--NOR--banding techniques were performed in 5 s+ patients and their parents and in all cases apparently identical prominent satellites were observed in both the proband and one of his parents. Nevertheless in some cases the proband's chromosome presents a decreased frequency of silver stained NORs and also has a smaller frequency of participation in acrocentric associations than the carrier parent's chromosome. The different behaviour of the s+ chromosomes presently studied may be caused by a complex regulatory mechanism depending upon each individual chromosome pool.