Nondisjunction in trisomy 21: Origin and mechanismsPetersen M.B.a,b · Mikkelsen M.b
aDepartment of Genetics, Institute of Child Health, Athens (Greece); bDepartment of Medical Genetics, The John F. Kennedy Institute, Glostrup (Denmark)
Chromosomal aneuploidy is a fundamental characteristic of the human species. In this review we summarize the knowledge about the origin and mechanisms of nondisjunction in human trisomy 21 that has accumulated during the last decade by using DNA polymorphism analysis. The first molecular correlate of nondisjunction in humans is altered recombination, meiosis I errors being associated with reduced recombination and maternal meiosis II errors with increased recombination between the nondisjoined chromosomes. Thus, virtually all maternal meiotic errors of chromosome 21 seem to be initiated in meiosis I. Advanced maternal age remains the only well documented risk factor for maternal meiotic nondisjunction, but there is, however, still a surprising lack of understanding of the basic mechanisms behind the maternal age effect.
© 2001 S. Karger AG, Basel
Request reprints from Dr. Michael B. Petersen, Department of Genetics,Institute of Child Health, “Aghia Sophia” Children’s Hospital,GR–11527 Athens (Greece); telephone: +30 1 77 53 030;fax: +30 1 77 00 111; e-mail: email@example.comProf. Margareta Mikkelsen, Department of Medical Genetics,The John F. Kennedy Institute, 7 Gl. Landevej,DK–2600 Glostrup (Denmark); telephone: +45 43 26 01 00;fax: +45 43 43 11 30; e-mail: firstname.lastname@example.org
The work in our laboratories was supported by E.C. BIOMED grants GENE-CT93-0015 and BMH4-CT96-0554 to the European Chromosome 21 Consortium, Else og Mogens Wedell-Wedellsborgs Fond, Smedemester Niels Hansen og hustru Johanne F. Frederiksen’s Legat, Brødrene Hartmanns Fond, Fru C. Hermansens Mindelegat, Direktør Jacob Madsens and Hustru Olga Madsens Fond, Kirstine Fonden, Kong Christian den Tiendes Fond, and Lily Benthine Lunds Fond.
Received: Received 19 May 2000;
manuscript accepted 16 June 2000.
Number of Print Pages : 5
Number of Figures : 0, Number of Tables : 2, Number of References : 65
Cytogenetics and Cell Genetics
Founded 1962 as Cytogenetics by H.P. Klinger
Vol. 91, No. 1-4, Year 2000 (Cover Date: 2000)
Journal Editor: H.P. Klinger, Bronx, N.Y.; M. Schmid, Würzburg
ISSN: 0301–0171 (print), 1422–9816 (Online)
For additional information: http://www.karger.com/journals/ccg