Gene May Inspire Male Contraceptive

Male Infertility Gene Mutation Could Lead to Male Infertility Treatments, Male Contraceptive

By Miranda Hitti
WebMD Health News

Reviewed By Louise Chang, MD

April 3, 2009 -- Scientists have discovered gene mutations linked to male infertility that may lead to new infertility treatments and a male contraceptive.

The mutations lie in the CATSPER1 gene, which makes a protein that's needed for normal sperm movement. The mutations make it hard for the CATSPER1 gene to make that essential protein, which could interfere with male fertility.

That could mean that the CATSPER1 gene could be a good target for male infertility treatment. And on the flip side, blocking the CATSPER1 gene might be a way to make a male contraceptive, the researchers write online in the American Journal of Human Genetics.

But don't expect a male "birth control" pill based on this study any time soon.

The research is at "a fairly early stage," researcher Michael Hildebrand, PhD, of the University of Iowa's otolaryngology department, tells WebMD.

"If we were to develop any therapy for people with infertility or if we were to consider male contraceptives ... we would still need to do studies in animal models to make sure the approach is both safe and effective -- and only then could we test it in humans," he says.

That process will take time.

"It would probably take at least a couple of years to complete the animal studies and then it would be additional years beyond that for clinical trials," Hildebrand says.

Male Infertility Gene Mutation

Hildebrand worked on the CATSPER1 paper with colleagues including University of Michigan graduate student Matthew Avenarius and Richard J.H. Smith, MD, of the University of Iowa's otolaryngology department and interdisciplinary program in genetics.

They noticed the CATSPER1 gene mutations while studying DNA from men of two Iranian families who had fertility problems.

They found that the men had a glitch in their two copies of the CATSPER1 gene, which hampered the CATSPER1 gene from making the sperm movement protein.

Previous studies have shown infertility in male mice lacking the CATSPER1 protein.

"This was a sperm-specific gene," says Hildebrand. "It's a calcium channel that's really essential for the normal movement of the sperm."

Next, the researchers want to search for similar mutations in other families and to study three other genes that are in the same gene family as CATSPER1, Hildebrand tells WebMD.

As for the male contraceptive possibility, Hildebrand says that some "preliminary work" has been done using antibodies to target the CATSPER1 protein.

"Both human and mice sperm treated with this particular antibody [were] associated with reduced fertility -- those sperm are not as able to fertilize an egg, at least not in a laboratory," Hildebrand says.

SOURCES: Avenarius, M. American Journal of Human Genetics, April 2, 2009; online edition. Michael Hildebrand, PhD, department of otolaryngology, University of Iowa.

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