title: Non-disjunction of chromosome 13.
abstract: We performed a molecular study with 21 microsatellites on a sample of 82 trisomy 13 conceptuses, the largest number of cases studied to date. The parental origin was determined in every case and in 89% the extra chromosome 13 was of maternal origin with an almost equal number of maternal MI and MII errors. The latter finding is unique among human autosomal trisomies, where maternal MI (trisomies 15, 16, 21, 22) or MII (trisomy 18) errors dominate. Of the nine paternally derived cases five were of MII origin but none arose from MI errors. There was some evidence for elevated maternal age in cases with maternal meiotic origin for liveborn infants. Maternal and paternal ages were elevated in cases with paternal meiotic origin. This is in contrast to results from a similar study of non-disjunction of trisomy 21 where paternal but not maternal age was elevated. We find clear evidence for reduced recombination in both maternal MI and MII errors and the former is associated with a significant number of tetrads (33%) that are nullichiasmate, which do not appear to be a feature of normal chromosome 13 meiosis. This study supports the evidence for subtle chromosome-specific influences on the mechanisms that determine non-disjunction of human chromosomes, consistent with the diversity of findings for other trisomies.
authors.affiliation: Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark. mb@imbg.ku.dk
authors.forename: Merete
authors.initials: M
authors.lastname: Bugge
authors.forename: Andrew
authors.initials: A
authors.lastname: Collins
authors.forename: Jens Michael
authors.initials: JM
authors.lastname: Hertz
authors.forename: Hans
authors.initials: H
authors.lastname: Eiberg
authors.forename: Claes
authors.initials: C
authors.lastname: Lundsteen
authors.forename: Carsten A
authors.initials: CA
authors.lastname: Brandt
authors.forename: Mads
authors.initials: M
authors.lastname: Bak
authors.forename: Claus
authors.initials: C
authors.lastname: Hansen
authors.forename: Celia D
authors.initials: CD
authors.lastname: Delozier
authors.forename: James
authors.initials: J
authors.lastname: Lespinasse
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Tranebjaerg
authors.forename: Johanne M D
authors.initials: JM
authors.lastname: Hahnemann
authors.forename: Kirsten
authors.initials: K
authors.lastname: Rasmussen
authors.forename: Gert
authors.initials: G
authors.lastname: Bruun-Petersen
authors.forename: Laurence
authors.initials: L
authors.lastname: Duprez
authors.forename: Niels
authors.initials: N
authors.lastname: Tommerup
authors.forename: Michael B
authors.initials: MB
authors.lastname: Petersen
mesh_terms: D000328:Adult; D002874:Chromosome Mapping; D002882:Chromosomes, Human, Pair 13; D005260:Female; D006801:Humans; D008297:Male; D008423:Maternal Age; D008540:Meiosis; D018895:Microsatellite Repeats; D009630:Nondisjunction, Genetic; D014314:Trisomy