Y chromosome microdeletions in Turkish infertile men
Indian Journal of Human Genetics
AIMS: To detect the frequency and types of both chromosomal abnor malities and Y chromosome microdeletions in infertile men attending to our university intracytoplasmic sperm injection ICSI/IVF centre and fertile control subjects in our patient population. SETTINGS AND DESIGN: A total of 50 infertile men who were referred to IVF center of Meram medical faculty were selected for the molecular azospermia factor (AZF) screening program. MATERIALS AND METHODS: Karyotype analysis and polymerase
... and polymerase chain reaction amplification using 15 Y-specific sequence-tagged sites of AZF region were done. RESULTS: The total prevalence of chromosomal abnormalities was found to be 10% (5/50), including 4 patients with numerical and 1 patient with structural abnormalities. Overall, 4 of the 50 patients tested (8%) exhibited deletions of the Y chromosome, 3 of them being azospermic and 1 of them oligospermic men.The frequency of the microdeletions in subgroups with azospermia and oligozoospermia was found to be 10.7% (3/29) and 4.7% (1/21) respectively. Microdeletions of AZFb and AZFc regions were detected in all of the 4 patients. Neither AZFa nor AZFd microdeletions were indicated. CONCLUSIONS: Our findings suggest that one must know whether there is a genetic cause for male infertility before patients can be subjected to ISCI or testicular sperm extraction (TESE)/ISCI treatment. About 15% of couples attempting pregnancy have reduced infertility; and in approximately 40-50% of all cases, the reason is male-factor infertility. [1, 2] Contributing factors such as infection, varicocele, endocrine disorders, spermatic duct obstruction, antisperm antibodies, etc., are described as idiopathic male infertility, accounting for over 20% of all male-factor infertility cases. However, in 60% of cases, male infertility could be the result of genetic factors, including cytogenetic abnormalities and microdeletions of the Y chromosome. [2, 3] Tiepolo and Zuffardi  have postulated the presence of a spermatogenesis locus located at Yq11, which is named 'azospermia factor (AZF) locus.' Molecular analyses of infertile men has identified four close subregions: AZFa, AZFb, AZFc and AZFd, within interval V and VI on Y q11.22-23.  In each region, candidate genes have been proposed, i.e., DFFRY in AZFa region, RBM (RNA binding motif) in AZFb region and DAZ (deleted in azospermia) in AZFc region.