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CATSPER2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

CATSPER2 gene

The CATSPER2 gene is critical for sperm hyperactivation, and its absence is associated with both male infertility and hearing loss.

Normal Function

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). It is one of four proteins that together form a hole (pore) that allows for the movement of charged calcium atoms (Ca2+) across the sperm cell membrane. Ca2+ is needed for a type of sperm motility called hyperactivation. Hyperactivation is characterized by vigorous movements of the sperm tail, allow the sperm to push through the membrane of the egg cell during fertilization.

Health Conditions Related to Genetic Changes

Deafness-infertility syndrome

Deafness-infertility syndrome is caused by a deletion of genetic material on the long (q) arm of chromosome 15. This condition is characterized by the combination of hearing loss and difficulty conceiving children (a condition called infertility).

The chromosomal region that is typically deleted in people with this condition 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, no CATSPER2 protein is produced. A lack of CATSPER2 protein impairs Ca2+ entry into the sperm cell and prevents hyperactivation. Without hyperactivation, sperm have decreased motility and are unable to push through the membrane of the egg cell and achieve fertilization.

Loss of another gene on chromosome 15, the STRC gene, is responsible for the hearing loss in affected individuals.

Other Names for This Gene

  • cation channel, sperm associated 2
  • CTSR2_HUMAN

Genomic Location

The CATSPER2 gene is found on chromosome 15.

Frequently Asked Questions

The deletion is inherited in an autosomal recessive pattern. If both parents carry the same deletion, each pregnancy has a 25 % chance of being affected, a 50 % chance of being a carrier, and a 25 % chance of being unaffected. Prenatal testing (amniocentesis or chorionic villus sampling) or pre‑implantation genetic diagnosis can identify affected embryos.
The same chromosomal region contains the STRC gene, which is essential for outer hair cell function in the cochlea. Deletion of STRC leads to sensorineural hearing loss, while deletion of CATSPER2 disrupts calcium entry in sperm, causing infertility. Thus, the deafness‑infertility syndrome is a combined effect of two adjacent gene losses.
There is no pharmacologic cure to restore hyperactivation. Assisted reproductive technologies are the mainstay: intracytoplasmic sperm injection (ICSI) bypasses the need for motile sperm by injecting a single sperm directly into an egg. For hearing loss, hearing aids or cochlear implants can provide significant benefit.
The first step is a detailed semen analysis showing reduced progressive motility or immotile sperm. If infertility persists, genetic testing is indicated: a karyotype or chromosomal microarray can detect a 15q deletion, and targeted sequencing of CATSPER2 confirms pathogenic variants. A normal karyotype with a 15q deletion may still be present, so microarray is preferred.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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