Y chromosome microdeletion is a genetic disorder caused by missing gene(s) on the Y chromosome. Microdeletion of the Y chromosome is the second most common genetic problem that causes male infertility after Klinefelter syndrome. Y chromosome microdeletions cause non-obstructive azoospermia or severe oligospermia. The gene which is responsible for sperm production is located in the AZF region on the long arm of the Y chromosome. Microdeletion occurs in the region AZFa, AZFb, and AZFc. Depending on which region the deletion is in, sperm production and sperm retrieval success can be different. For example, sperm can be found in 60-80% of men with AZFc deletion by micro TESE. The probability of obtaining mature sperm is high in AZFc, while AZFa and AZFb are low.
Patients with AZFa; AZFb; AZFc; AZFb+c; AZFa+b+c microdeletion are strong candidates for ROSI technique. In the ROSI technique, the egg is fertilized with spermatids. Since Y chromosome microdeletion is likely to be passed from father to son, genetic testing should be done before embryos are transferred to the uterus.
