Nondisjunction of chromosome 21: comparisons of cytogenetic and molecular studies of the meiotic stage and parent of origin.


Journal Article

In the present report, we summarize studies aimed at examining the reliability of chromosome heteromorphisms in analyses of chromosome 21 nondisjunction. We used two cytogenetic approaches--fluorescent in situ hybridization (FISH) to repetitive sequences on 21p and traditional Q-banding--to distinguish chromosome 21 homologues and then compared the results of these studies with those obtained by DNA markers. Using a conservative scoring system for Q-banding and FISH heteromorphisms, we were able to specify the parental origin of trisomy in 10% of cases; in contrast, DNA marker studies were informative for parental origin in almost all cases. The results of the molecular and cytogenetic studies of parental origin concurred in all cases in which assignments were made independently using both techniques. However, in 4 of 13 cases in which the molecular studies contributed to the interpretation of the cytogenetic findings, the two results did not agree with respect to the meiotic stage of nondisjunction. A relatively high frequency of crossing-over on either the short arm or proximal long arm of chromosome 21 could explain these results and may be a mechanism leading to nondisjunction.

Full Text

Cited Authors

  • Lorber, BJ; Grantham, M; Peters, J; Willard, HF; Hassold, TJ

Published Date

  • December 1992

Published In

Volume / Issue

  • 51 / 6

Start / End Page

  • 1265 - 1276

PubMed ID

  • 1463010

Pubmed Central ID

  • 1463010

Electronic International Standard Serial Number (EISSN)

  • 1537-6605

International Standard Serial Number (ISSN)

  • 0002-9297


  • eng