Analysis of aneuploidy for chromosomes 13, 21, X and Y by multicolour fluorescence in situ hybridisation (FISH) in a 47,XYY male.
The frequency of aneuploid sperm was assessed by fluorescence in situ hybridisation (FISH) in a 47,XYY male previously studied by sperm karyotyping. A total of 20,021 sperm were studied: 10,017 by two-colour FISH for chromosomes 13 and 21 and 10,002 by three-colour FISH for the sex chromosomes using chromosome 1 as an autosomal control for diploidy and lack of hybridisation. Results were compared with more than 500,000 sperm from 18 normal men. The frequencies of X-bearing (49.4%) and Y-bearing sperm (49.8%) were not significantly different from 50% as shown in our sperm karyotyping study. There was no significant increase in the frequency of diploid sperm compared with control donors. There was a significant increase in the frequency of disomy for chromosome 13 (p < 0.0001) and XY disomy (p = 0.0008) compared with control donors. However, since the frequency of disomy was 0.40% for chromosome 13 and 0.55% for XY disomy, it is not surprising that these increases were not discovered previously in our analysis of 75 sperm karyotypes. Our results suggest that the extra Y chromosome is eliminated during spermatogenesis in the majority of cells but that there may be a small but significant increase in the frequency of aneuploid sperm in these men.
Department of Genetics, Alberta Children's Hospital, Calgary, Canada. renee@ach.ucalgary.ca
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Martin
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McInnes
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Rademaker
D000328:Adult; D000782:Aneuploidy; D002882:Chromosomes, Human, Pair 13; D002891:Chromosomes, Human, Pair 21; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008297:Male; D013094:Spermatozoa / Q000166:cytology / Q000502:physiology; D014960:X Chromosome; D014998:Y Chromosome