US scientists say CATSPER1 could be the key gene for male infertility treatment and also for evolving a male contraceptive pill.
It was while investigating the genetic causes of deafness, the scientists stumbled upon CATSPER1, it has been reported in University of Iowa in the April 2 online edition of the American Journal of Human Genetics
The research team, which included scientists from the University of Social Welfare and Rehabilitation Sciences in Tehran, Iran, identified males in two families that had different DNA mutations in the CATSPER1 gene suffered from infertility.
DNA analysis revealed two different mutations -- one in each family -- but both mutations would likely lead to either a very truncated, non-functional version of the protein, or no protein at all. Neither mutation was found in the DNA of 576 Iranian individuals who were screened as controls.
Tests on mice have previously found CATSPER1 mutations cause infertility because they affect sperm "hyperactivation" - the ability to move with the required energy and speed to enter the female egg during fertilisation.
"We have identified CATSPER1 as a gene that is involved in non-syndromic male infertility in humans, a finding which could lead to future infertility therapies that replace the gene or the protein. But, perhaps even more importantly, this finding could have implications for male contraception," said Michael Hildebrand, co-lead author of the study and a UI postdoctoral researcher in otolaryngology at the UI Roy J. and Lucille A. Carver College of Medicine.
He added: "Identification of targets such as the CATSPER1 gene that are involved in the fertility process and are specific for sperm - potentially minimising side effects of a drug targeting the protein's function - provide new targets for a pharmacological male contraceptive."
A potential approach is to target CATSPER1 is immunocontraception, where antibodies are developed that bind to a targeted protein and block its function.
But the researchers stress that immunocontraception is still in the early stages of development and that, in order to be useful, it will need to be proven effective, safe and reversible.