What are Y Chromosome microdeletions?

What are Y Chromosome microdeletions?

The Y chromosome is a gene which assists in production of sperm. It is the sex determining factor in males and is inherited from one generation to the next, forming the genetic link. In humans, the male has 2 chromosomes Y and X and the female also has 2 – XX. So, if the Y chromosome is present, it determines the gender of the baby as male.

Sometimes, there are genes missing in these Y chromosomes, and this is known as Y Chromosome Microdeletions. These missing genes are known to cause male infertility. However, patients with this disorder sometimes have no symptoms and tend to lead normal lives, even fathering a child naturally.

Azoospermia is the condition where there is absence of sperm in the semen. Often, the Y chromosome microdeletion occurs at the region marked as the Azoospermia Factor (AZF), which is divided into 3 portions – a, b and c.  The Y chromosome physical structure has two “arms” – the long arm and the short arm.  The AZF regions are all located in the long arm. Any changes in this region of the chromosome will result in Azoospermia or Oligozoospermia (low sperm count). By doing a simple semen analysis, a patient and clinician can find out if there is an absence of sperm in the sample (Azoospermia) or very low sperm count (Severe Oligozoospermia).

Each region of the AZF region is important with its effects on the male reproductive health.

AZFa is the main region that supports sperm cell production. If there is a deletion in this region, males will not be able to produce healthy sperms even though they will be able to nourish the sperm cells. Treatment for this condition which is known as Sertoli cell-only syndrome, is rather difficult.

AZFb is the region that assists with the growth and maturity of sperm. If there are deletions in this region, the sperm cells do not mature and, even though they are present in the testicular region, they are not able to reproduce.

AZFc is the distant region of the “long arm” and deletions in this area are most common in patients. AZFc does not contribute much to sperm production and hence a deletion in this region of the gene, results in low sperm count. However, this condition is treatable as often, patients have live sperm in the testicles even though there may not be any sperm present in the ejaculate sample. In this case sperm retrieval techniques may be employed to retrieve sperm for use in ICSI or IVF.

Y Chromosome Microdeletion tests are usually conducted in males with Azoospermia or other infertility disorders, to check whether there are any genes missing in their Y chromosome – especially when they have no outward symptoms and once the usual physical examination and other tests are done.

The DNA is retrieved from leukocytes in the male’s blood sample, to identify the Y chromosome and to study the defects or disorders in the chromosomal level. The test helps to identify the reason for infertility in the man. It can also identify the extent of the microdeletions in the regions of the AZF. This, in turn, helps the doctor to work out the correct treatment method for sperm retrieval.

The Y chromosome microdeletion test is not harmful to the human body and, if you feel the need to have the test conducted, you can contact us at Andrology Center, Coimbatore, on +91 944 379 3934. More details will be provided to you at that time.

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