Letters Section Editor: Robert M. Golub,
MD, Senior Editor.
To the Editor: It is possible that improper
heterochromatinization of X chromosomes in XY bodies of male heterozygous BRCA1 carriers may lead such male sperm cells to be less
viable, given that products of the BRCA1 gene are
presumed to play a role in this process.1 Thus,
male heterozygous carriers would be expected to have a greater proportion
of female offspring. Indeed, de la Hoya et al2 reported
an excess of females among the offspring of BRCA1 mutation
carriers but no such sex-ratio distortion affects the offspring of BRCA2 carriers. However, these results might have reflected an ascertainment
bias of carriers through affected females.3 Because
penetrance is higher at younger ages in BRCA1 than
in BRCA2 female carriers,4 this
bias could be stronger in BRCA1 than in BRCA2-associated families.
Feunteun J, Chompret A, Helbling-Leclerc A, et al. Sex Ratio Among the Offspring of. JAMA. 2004;292(6):687–688. doi:10.1001/jama.292.6.687
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