[Activity of ribosomal genes and the association with acrocentric chromosomes in trisomy 21 and habitual abortion].
The frequency of silver stain of the nucleolus organizer regions (NOR's) an indicator of the transcriptional activity of the DNAr, and the frequency of the association between acrocentric chromosomes (A.A.C.), possible indicator of the non-disjunction risk, were studied in the chromosomes in metaphase of eight married couples with regular 21 trisomy children, five couples that have had consecutive miscarriages and fifteen control normal persons, eight men and seven women. In this three groups the mean age was 30 years and they were compared according to sex. Another seven couples, with a mean age of 52 years also parents of 21 trisomic were compared against the group of young parents of 21 trisomics in order to analyze the age effect. Moreover there were studied the trisomic children of eight of the above couples in order to find out the effect of the supernumerary 21 chromosome. In all the groups the correlation coefficients between the frequency of NOR's-Ag+ and the A.A.C. were determined. It was found that the young group of parents of trisomic and the couples with consecutive miscarriages, both men and women, had a significant increased frequencies of NOR's-Ag+ and A.A.C. in comparison to controls. In the parents of trisomic, either men or women it was found a significant diminished level in the frequency of NOR's-Ag+ when the age increased, meanwhile raise in the frequency of A.A.C. with the increase of age was observed only in the women. A positive correlation between the frequencies of NORs-Ag+ and A.A.C. was found in the women of the control group and in the young mothers of trisomic.(ABSTRACT TRUNCATED AT 250 WORDS)
Leal-Garza
C H
CH
Unidad de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social.
Riojas-Valdes
V M
VM
Garza-Chapa
R
R
D000026:Abortion, Habitual / Q000235:genetics*; D000328:Adult; D004275:DNA, Ribosomal / Q000235:genetics*; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009630:Nondisjunction, Genetic; D009697:Nucleolus Organizer Region / Q000378:metabolism*; D010290:Parents; D011247:Pregnancy; D012335:RNA, Ribosomal / Q000096:biosynthesis*
D004275:DNA, Ribosomal; D012335:RNA, Ribosomal
Actividad de genes ribosomales y asociación de cromosomas acrocéntricos en la trisomía 21 y el aborto habitual.