Despite knowing about the defect and its inheritance pattern, couples might not be deterred from trying to have sons, said Page.
"I am told by clinicians with whom I collaborate that most of the couples they treat would simply wish to go ahead with having children via ICSI. Some, in contrast, might elect to avoid transmitting the infertility by using donor sperm or by adopting, and others could decide to have only daughters by genetically testing the fertilized embryos to determine their sex and only having female embryos implanted, " said Page.
Page cautioned that genetic engineering of sperm to correct the defect is still a farfetched notion "because, of course, any such attempt at gene repair would carry with it the potential for collateral damage."
A more likely remedy, says Page, is the possibility that affected males, who may produce normal amounts of sperm during puberty and young adulthood, may decide to have their sperm harvested for future use. To date, however, scientists have not conducted careful clinical studies to explore the link between changing sperm counts and age, he said.
"We only know now that men in their twenties and thirties with AZFc deletions can have considerable variability in the number of sperm in their semen." If sperm counts do prove to be higher in younger affected males, said Page, they might have their sperm harvested and stored until they are ready to start a family.
The latest findings emphasize the importance of basic research in understanding the mechanisms by which Y chromosome deletions cause infertility, said Page. "We really don't know why this missing piece of the Y chromosome leads to spermatogenic failure, but we are learning more and more about the missing genes," he said.
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
1-Jul-1999