Comparative study of microsatellite and cytogenetic markers for detecting the origin of the nondisjoined chromosome 21 in down syndrome
- John F. Kennedy Institute, Glostrup (Denmark)
- Johns Hopkins Univ., Baltimore, MD (United States)
- Univ. of Antwerp (Denmark)
- Univ. of Pittsburgh, PA (United States)
Nondisjunction in trisomy 21 has traditionally been studied by cytogenetic heteromorphisms. Those studies assumed no crossing-over on the short arm of chromosome 21. Recently, increased accuracy of detection of the origin of nondisjunction has been demonstrated by DNA polymorphism analysis. The authors describe a comparative study of cytogenetic heteromorphisms and seven PCR-based DNA polymorphism analysis. They describe a comparative study of cytogenetic heteromorphisms and seven PCR-based DNA polymorphisms for detecting the origin of the additional chromosome 21 in 68 cases of Down syndrome. The polymorphisms studied were the highly informative microsatellites at loci D21S120, D21S192, IFNAR, D21S156, HMG14, and D21S171. The meiotic stage of nondisjunction was assigned on the basis of the pericentromeric markers D21S215, D21S120, and D21S192. Only unequivocal cytogenetic results were compared with the results of the DNA analysis. The parental and meiotic division origin could be determined in 51% of the cases by using the cytogenetic markers and in 88% of the cases by using the DNA markers. Although there were no discrepancies between the two scoring systems regarding parental origin, there were eight discrepancies regarding meiotic stage of nondisjunction. The results raise the possibility of recombination between the two marker systems, particularly on the short arm. 46 refs., 2 figs., 3 tabs.
- DOE Contract Number:
- FG02-89ER60857
- OSTI ID:
- 5079846
- Journal Information:
- American Journal of Human Genetics; (United States), Vol. 51:3; ISSN 0002-9297
- Country of Publication:
- United States
- Language:
- English
Similar Records
Understanding the mechanism(s) of mosaic trisomy 21 by using DNA polymorphism analysis
Structural rearrangements of chromosome 15 satellites resulting in Prader-Willi syndrome suggest a complex mechanism for uniparental disomy