**Y-microdeletion and fertility:**

Y-chromosome microdeletions (YCMs) are the most common known structural chromosomal abnormalities for spermatogenic impairment. As high as 25–55% of the patients with hypospermia, sperm maturation arrest and SCO syndrome and 5–25% of the patients with severe oligozoospermia or azoospermia are established to have YCMs [21].

Deletions occur in three specific subregion - AZFa, AZFb and AZFc of the AZF in the long arm of the Y chromosome. Deletions in these regions are associated with:

AZFa region partial removal - hypo-spermatogenesis.

AZFa region complete deletion - inhibits the production and maturation of germ cells; SCO syndrome.

AZFb region deletions - pre-meiotic spermatogenic arrest or SCO syndrome; azoospermia, oligozoospermia.

AZFc region partial deletions - hypospermatogenesis.

AZFc region complete deletion - SCO syndrome and alterations in spermatocyte maturation [22].

Different studies indicate highest incidence of Y-microdeletion in the AZFc region, followed by AZFa+b + c; AZFb+c; AZFb; AZFa; and partial AZFa region deletion [23–25].

Passing genetic impairment to the offspring should be of high caution when sperm freezing and consequent ART is discussed.
