CATSPER2

The CATSPER2 gene provides instructions for producing a protein that is found in the tail (flagellum) of sperm cells. The CATSPER2 protein plays a role in sperm cell movement (motility) and is required for sperm cells to push through the outside membrane of the egg cell during fertilization. The CATSPER2 protein is embedded in the membrane of the sperm tail and is necessary in order for positively charged calcium atoms (calcium cations) to enter the cell. Calcium cations are needed for a type of sperm motility called hyperactivation. Hyperactivation is characterized by vigorous movements of the sperm tail, which are required for the sperm to push through the membrane of the egg cell during fertilization.

sensorineural deafness and male infertility - associated with the CATSPER2 gene

The symptoms of sensorineural deafness and male infertility are caused by a deletion of genetic material on the long (q) arm of chromosome 15. The chromosomal region that is typically deleted contains multiple genes, including the CATSPER2 gene. People with this condition have the deletion in both copies of chromosome 15 in each cell. As a result of the deletion, affected individuals are missing both copies of the CATSPER2 gene, and no CATSPER2 protein is produced. A lack of CATSPER2 protein impairs calcium entry into the sperm cell, which decreases motility and prevents hyperactivation. Lack of hyperactivation results in sperm that are unable to push through the membrane of the egg cell and achieve fertilization. These sperm abnormalities are the cause of infertility in affected males.