Reduction of the activity of ribosomal genes with age in Down's syndrome

The hypothesis of the coparticipation of ribosomal genes in controlling the differential expression of genes with age is analyzed in Down's syndrome. The activity of ribosomal genes was tested cytogenetically by Ag-stained nucleolar organizer regions and by satellite association in lymphocytes from 40 patients with Down's syndrome. Twenty patients were between 0 and 25 years old, and the others were between 29 and 48 years old. Our results showed a significant decrease with regard to total Ag staining and in relation to each chromosome pair in the older Down's syndrome group as compared with the younger group. The total number of associated chromosomes and the number of associations of each chromosome pair were both significantly lower. The results show a decreased activity of ribosomal genes with age. This reduction may originate from changes in regulation and expression of these genes that might result in differing cell translation ability.