CATSPER1-related nonsyndromic male infertility

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

CATSPER1-related nonsyndromic male infertility is a condition that affects the function of sperm, leading to difficulty conceiving children (a condition called infertility). People with this condition produce sperm that have decreased movement (motility). Affected individuals may also produce fewer sperm cells or sperm cells that are abnormally shaped. These sperm abnormalities prevent people with this condition from conceiving without assisted reproductive technologies.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Variants (also called mutations) in the CATSPER1 gene cause CATSPER1-related nonsyndromic male infertility. The CATSPER1 gene provides instructions for producing a protein that is found in the tail of sperm cells. The CATSPER1 protein is involved in the movement of the sperm tail, which propels the sperm forward and is required for sperm cells to push through the outside membrane of the egg cell during fertilization.

CATSPER1 gene variants cause sperm cells to produce altered versions of the CATSPER1 protein that are not functional or that can be quickly broken down (degraded) by the cell. Sperm cells that are missing a functional CATSPER1 protein have decreased motion in their tails and move more slowly than normal. These sperm cells cannot push through the outside membrane of the egg cell. As a result, the sperm cells cannot reach the inside of the egg cell to achieve fertilization.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell must have a variant to cause the disorder. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

Males (with one Y chromosome) who have two CATSPER1 gene variants in each cell have CATSPER1-related nonsyndromic male infertility. Females (with two X chromosomes) who have two CATSPER1 gene variants in each cell have no symptoms because they do not produce sperm and the changes only affect sperm function.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

The prevalence of CATSPER1-related nonsyndromic male infertility is unknown.

Understanding terms used in the source

These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.

Affected

This term applies to a family member who is diagnosed with the same condition as the individual who is the primary focus of investigation (the proband).

Which doctor should you see?

The suggested department for discussing CATSPER1-related nonsyndromic male infertility is Reproductive Medicine, with a fertility specialist; gynaecologist or urologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What information is needed from each relevant partner?
• What can the proposed tests explain, and what are their limitations?
• What are the likely next steps, time commitments and costs?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for CATSPER1-related nonsyndromic male infertility. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.