The Grapevine

Genetics May Be Underlying Cause Of Infertility; New Technology Identifies Genetic Diseases

Genetics
Researchers compare mice and human gene databases to identify which are capable of mutating to cause infertility. Photo courtesy of Shutterstock

On a list of what causes infertility in women, the Department of Health and Human Services lists ovulation problems, blocked fallopian tubes, uterus shape, and fibroids, which are lumps of extra uterine muscle inside the uterus. But should they also list genetics? According to a new study published in the Proceedings of the National Academy of Sciences, a gene mutation may result in infertility.

“Infertility is a prevalent health issue, affecting [about 15 percent] of couples of childbearing age,” study authors Priti Singh and Dr. John C. Schimenti, of the biomedical science department at Cornell University, wrote. “Nearly one-half of idiopathic infertility cases are thought to have a genetic basis, but the underlying causes are largely unknown. Traditional methods for studying inheritance, such as genome-wide association studies and linkage analyses, have been confounded by the genetic and phenotypic complexity of reproductive processes.”

In order to address and understand these complexities, the authors developed their own strategy to identify gene mutations that could cause infertility among human population. These mutations are called single nucleotide polymorphisms (SNPs) and, according to researchers, SNPs represent the different DNA building blocks known as nucleotides. The idea is that if researchers can single out any one SNP, they could potentially offer their patients genetic tests to determine infertility.

Researchers used genome editing technology to edit genes that are known to cause infertility in mice, before using a database of human genetic variations to find any human equivalents. Of the four specific genes researchers tested, one caused infertility, which they admitted was a surprise.

“We were surprised at how poor the existing, commonly-used algorithms were at predicting deleterious SNPs,” Schimenti said. “But with this technology, we are starting to identify those SNPs that really do cause infertility in humans.”

Schimenti and Singh added although infertility is “highly prevalent,” most patients don’t know about the wealth of underlying genetic causes. Sperm and egg production is so complex that it just ends up confounding the effort to better explain these particular causes of human fertility.

But with this technology, Schimenti said future research and studies can use it to establish permanent resources of genes that have the potential to cause infertility and other genetic diseases. Schimenti himself will collaborate with the Weill Institute for Cell and Molecular Biology to further his research in genome editing to identify more infertility-causing SNPs.

“Furthermore,” both authors concluded, “because this approach can be applied to any genetic disease, it should be a powerful tool in the era of personalized genomic medicine.”

Source: Singh P and Schimenti JC. The genetics of human infertility by functional interrogation of SNPs in mice. Proceedings of the National Academy of Sciences. 2015.

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