Every healthy male carries 46 chromosomes, arranged in 23 pairs. One of those pairs determines biological sex — an X and a Y chromosome. While the X chromosome is shared with females, the Y chromosome is unique to males and holds genetic regions that are crucial for sperm production.
What is Y Chromosome?
The Y chromosome isn’t just a single unit — it’s divided into several specialized regions. Two outer areas, known as pseudoautosomal regions, are shared with the X chromosome. Deeper inside lie two distinct zones: the heterochromatic regions, which provides structural support, and the euchromatic regions, which carries a small section of DNA that is the genetic code necessary for sperm development.
These two internal regions combine to form what’s called the non-recombinant region — or MSY — which contains the AZF region, short for “azoospermia factor.” This region is essential for the normal development of sperm cells.
Within the AZF region, there are three key sections: AZFa, AZFb, and AZFc. The journey of sperm development begins in AZFa, continues in AZFb, and is completed in AZFc. Any deletion in these areas — even if small — can disrupt the entire process of sperm production.
Who is Y Chromosome Microdeletion Test Recommended for?
In certain cases, especially when sperm count is extremely low or absent, the underlying cause may be a microdeletion in one of these AZF zones. This is particularly common in men with non-obstructive azoospermia or severely compromised sperm parameters.
For these patients, Y chromosome microdeletion testing can offer clarity. It is often recommended when:
- A man is planning IVF with ICSI
- A previous attempt at micro-TESE (surgical sperm extraction) has failed
- There is a family history of genetic abnormalities
- The analysis shows non-obstructive azoospermia (no sperm due to testicular failure, not a blockage)
- There are abnormally high levels of follicle-stimulating hormone (FSH)—a sign the testicles may not be producing sperm properly
- The testicls are small or underdeveloped without a clear anatomical explanation
- Or simply, when all other possible causes have been ruled out
What Can the Results Show?
For many, the results of this test can reshape the course of their fertility journey. A negative result brings relief — no deletions were found, and chances for obtaining sperm during microsurgical sperm retrieval remain high. But even if a microdeletion is detected, all hope is not lost.
Some deletions, particularly in the AZFc region, may still allow for successful sperm retrieval through Micro-TESE, with a success rate of up to 80%. On the other hand, deletions in AZFa or AZFb typically mean that sperm production has stopped at a much earlier stage, making biological parenthood using one’s own sperm highly unlikely.
Further, these genetic deletions may be passed on to male offspring. That’s why, in such cases, patients who proceed with IVF are often advised to undergo PGT-A — preimplantation genetic testing for aneuploidy. PGT-A may be used to select a female embryo, thereby avoiding the inheritance of the genetic defect on the Y chromosome. Some couples may also choose to move forward using donor sperm instead.
How is the Test Performed?
Testing for Y chromosome microdeletions is quick and non-invasive. At Genomics – Reproductive Genetics Center, our in-house lab, we use the PCR method — the gold standard for this type of genetic screening. The test is performed using a simple saliva sample, from which DNA is extracted and analyzed to identify deletions in the AZF regions.
Results are typically available within 7 working days, and your doctor will guide you through every step, from specimen collection to interpretation of results and decision-making.
What Happens Next?
When the reasons behind infertility remain unclear, this test can offer answers — and with those answers, the confidence to move forward. Whether that means pursuing Micro-TESE, selecting embryos carefully through PGT-A, or considering donor options, knowing what’s happening at the genetic level gives you and your care team the power to plan with knowledge, precision and compassion.
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Frequently Asked Questions (FAQs)
We know that fertility care often brings up many questions — and that every journey is different. Below you’ll find answers to some of the most common questions our patients ask.
What does a negative result mean?
It means no deletion was found in the AZF region — sperm retrieval may be possible.
What if a microdeletion is found?
Your doctor will explain what the deletion means, how it affects fertility, and whether options like Micro-TESE or IVF with ICSI remain viable.
Can microdeletions be passed on to children?
Yes — especially to male children. That’s why PGT-A is often advised to help prevent inheritance.
