OVERVIEW

What is Y chromosome microdeletion?

Y chromosome microdeletion primarily refers to small missing segments on the Y chromosome in males.

The Y chromosome contains genes related to sperm production, known as azoospermia factor (AZF) genes. These genes are further divided into regions a, b, and c. Deletion in any of these regions can affect sperm quantity and quality, potentially impacting fertility ^[1].

Y chromosome microdeletion generally has minimal impact on overall health, with most patients exhibiting normal male characteristics and sexual function.

Is Y chromosome microdeletion common?

Y chromosome microdeletion is relatively rare overall but ranks as the second leading cause of male infertility ^[2].

Is Y chromosome microdeletion congenital or acquired? Is it hereditary?

Y chromosome microdeletion is a congenital condition.

Since it is located on the Y chromosome, it can be inherited by male offspring but not by female offspring.

Patients with Y chromosome microdeletion can opt to conceive female offspring with medical assistance or use donor sperm from sperm banks to avoid passing the condition to the next generation.

SYMPTOMS

What are the common manifestations of Y chromosome microdeletion?

Y chromosome microdeletion generally does not affect the patient's health but may lead to the following manifestations:

• Most patients exhibit azoospermia (no sperm production) or very low sperm count;

• Some patients may have a normal sperm count, but the sperm quality is poor;

• A small number of patients may experience testicular shrinkage, among other symptoms ^[3].

What complications can Y chromosome microdeletion cause, and how should they be addressed?

Due to low sperm count or poor sperm quality, most patients find it difficult to conceive naturally (difficulty in pregnancy or a high risk of miscarriage).

However, patients need not be overly anxious, as medical interventions (such as medication or assisted reproductive technologies like IVF) can still help them have children.

CAUSES

What is the cause of Y chromosome microdeletion?

Y chromosome microdeletion is a congenital chromosomal abnormality.

Most Y chromosome microdeletions are caused by de novo mutations, meaning the mutation occurs in the patient themselves.

A small number of Y chromosome microdeletions result from vertical transmission from the paternal lineage, where the mutation occurs in the father's body and expands during transmission, ultimately leading to infertility in offspring.

DIAGNOSIS

When should one seek medical attention for Y chromosome microdeletion?

If a couple has difficulty conceiving despite regular sexual activity, or if the wife has experienced multiple unexplained miscarriages, it is advisable to seek medical evaluation to determine whether Y chromosome microdeletion is present.

Which department should one visit for Y chromosome microdeletion?

It is recommended to consult the Reproductive Genetics Department.

How is Y chromosome microdeletion diagnosed?

Currently, the primary method involves drawing a small blood sample for genetic testing to determine whether a Y chromosome microdeletion exists.

How to interpret a Y chromosome microdeletion test report?

In the test report, the first thing to check is whether a Y chromosome microdeletion is detected:

• If the results indicate no Y chromosome microdeletion under the testing conditions, the likelihood of having a microdeletion is very low. The patient is advised to consult a doctor for further examinations (e.g., semen analysis, sperm motility tests) to identify the cause of infertility.

• If the results confirm a Y chromosome microdeletion, the specific region of the deletion should be noted, as different regions have varying implications:

  1. AZFa region deletion: Rare, indicating the absence of sperm production in the patient.
  2. AZFb region deletion: Indicates the absence of sperm production in the patient.
  3. AZFc region deletion: The most common type, with varied manifestations. Some patients may still produce sperm, but sperm count declines with age, and quality may deteriorate. Therefore, these patients are advised to conceive early or consider sperm freezing if possible.

How long does it take to receive Y chromosome microdeletion test results?

Results typically take 7–15 working days, though this may vary by region.

TREATMENT

How is Y chromosome microdeletion treated? How to have children?

Y chromosome microdeletion generally does not require special treatment and does not affect health.

Patients with fertility needs should clarify the condition of the deletion region to evaluate the testis's ability to produce sperm and determine whether testicular sperm extraction (TESE) can be performed to obtain their own sperm and the next treatment plan.

• For those who produce sperm: Under the guidance of a doctor, drug treatment can be administered. If drug treatment is ineffective, testicular sperm extraction can be performed to screen for healthy sperm, and assisted reproductive technologies such as IVF can be used to have children. It should be noted that male offspring will inherit the disease, so it is recommended to selectively conceive female offspring with the help of a doctor ^[3].

• For those who do not produce sperm: Testicular sperm extraction is not recommended to avoid unnecessary surgery and suffering. Healthy sperm can be obtained from a sperm bank for IVF.

Can Y chromosome microdeletion be cured?

This is a genetic disease and currently cannot be cured with medication or other methods.

DIET & LIFESTYLE

What should be noted in life/diet regarding Y chromosome microdeletion?

There are no special precautions needed in life or diet, and the patient's health will not be affected.

PREVENTION

Can Y chromosome microdeletion cause fetal developmental arrest?

Some wives of patients with Y chromosome microdeletion can conceive naturally, but the risk of pregnancy failure is relatively high.

During pregnancy, due to sperm quality issues, the fetus is prone to developmental arrest, leading to unexplained miscarriage in the mother.

Can Y chromosome microdeletion be prevented? How to prevent it?

Y chromosome microdeletion is a congenital genetic disorder, and no highly effective preventive measures have been discovered so far.