Recent Developments in Male Factor Infertility Research

by Dr. Susan Daniel

Scientists at UC Davis have discovered that up to 25% of men carry two copies of a defective gene known as DEFB126 which results in the production of abnormal β-defensin 126.

β-defensin 126 is a protein that is made in the epididymis of the male reproductive tract. It attaches to sperm and coats their surfaces to allow sperm to swim through the mucus in the female reproductive tract. The protein acts by protecting the sperm from attack by the woman's immune system.

Men with abnormal β-defensin 126 generally have a normal semen analysis (sperm density, motility, progression, and morphology), but their sperm are unable to swim through the cervical mucus and up through the uterus and Fallopian tubes to fertilize eggs after ovulation. The scientists hope that they will be able to develop a simple test for the presence of the abnormal form of the protein so that couples having difficulty becoming pregnant can be directed to the best treatment option.

“Key to male infertility may be sperm coat protein”. 21 July 2011. http://www.medicalnewstoday.com/releases/231469.php