Abstract
To test the hypothesis that there is a genetic predisposition to non-disjunction (NDJ) associated with DNA sequences on chromosome 21 (C21), we used DNA polymorphism haplotypes for C21s to examine the distribution of different C21s in Down Syndrome (DS) and control families. The C21s from 20 Greek families with DS and 27 control Greek families have been examined for haplotypes using four common polymorphic sites adjacent to two very closely linked single copy DNA sequences which map to the proximal long arm of C21. Three haplotypes ++++, +——, -+++ with frequencies of 43/108, 24/108, 23/108, respectively, account for the majority of C21s in the control families. However, in the DS families haplotype -+++ was commonly associated with C21s which underwent NDJ (frequency 21/50, X2 = 9.6, p=0.023, df=3). There was no difference between the haplotypes of C21s which did not participate in NDJ in the DS families and those of the control families. In addition, DS and control families did not differ in the distribution of haplotypes for two DNA polymorphisms on chromosome 17. We conclude that the C21 which is marked in Greeks by -+++ for the four polymorphic sites examined is found much more commonly in chromosomes which participate in NDJ than in controls. We propose an increased tendency for NDJ due to DNA sequences associated with a subset of C21s bearing this haplotype.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Antonarakis, S., Kittur, S., Metaxotou, C. et al. 800 ANAIXSIS OF DNA HAPLOTYPES SUGGESTS A GENETIC PREDISPOSITION TO TRISOMY 21 ASSOCIATED WITH DNA SEQUENCES ON CHROMOSOME 21. Pediatr Res 19, 244 (1985). https://doi.org/10.1203/00006450-198504000-00830
Issue Date:
DOI: https://doi.org/10.1203/00006450-198504000-00830