Non-disjunction of chromosome 13.
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.
Bugge
Merete
M
Wilhelm Johannsen Centre for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark. mb@imbg.ku.dk
Collins
Andrew
A
Hertz
Jens Michael
JM
Eiberg
Hans
H
Lundsteen
Claes
C
Brandt
Carsten A
CA
Bak
Mads
M
Hansen
Claus
C
Delozier
Celia D
CD
Lespinasse
James
J
Tranebjaerg
Lisbeth
L
Hahnemann
Johanne M D
JM
Rasmussen
Kirsten
K
Bruun-Petersen
Gert
G
Duprez
Laurence
L
Tommerup
Niels
N
Petersen
Michael B
MB
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