BACKGROUND

It is unclear whether frequency of sperm aneuploidy is associated with risk of fathering children with trisomy.

METHODS

We recruited 36 families with a boy with Klinefelter syndrome (KS), interviewed the fathers about their exposures and medical history, received a semen sample from each father, and collected blood samples from the mother, father and child. We applied a multicolour fluorescent in-situ hybridization assay to compare the frequencies of sperm carrying XY aneuploidy and disomies X, Y and 21 in fathers of maternally and paternally inherited KS cases.

RESULTS

Inheritance of the extra X chromosome was paternal in 10 and maternal in 26 families. Fathers of paternal KS cases produced higher frequencies of XY sperm (P = 0.02) than fathers of maternal KS cases. After controlling for age, the major confounding variable, the difference between the two groups was no longer significant (P less-than-or-equal 0.2). Also, there were no significant differences between the parental origin groups for disomy X, Y or 21.

CONCLUSIONS

Men who fathered a child with a Klinefelter syndrome produced higher frequencies of XY sperm aneuploidy, which is explained, in part, by both paternal age and parent of origin.