Genetic aspects of human male infertility: the frequency of chromosomal abnormalities and Y chromosome microdeletions in severe male factor infertility.

OBJECTIVE

The main purpose of this study is to detect the frequency and type of both chromosomal abnormalities and Y chromosome microdeletions in patients with severe male factor infertility and fertile control subjects. The association between the genetic abnormality and clinical parameters was also evaluated.

METHODS

This study was carried out in 208 infertile and 20 fertile men. Results of 208 patients, 119 had non-obstructive azoospermia and 89 had severe oligoasthenoteratozoospermia (OAT). Seventeen out of 119 (14.3%) azoospermic patients and two out of 89 (2.2%) patients with OAT had Y chromosome microdeletions. In total, 19 cases with deletions were detected in 208 infertile men, with a frequency of 9.1%. The AZFc locus, mainly DAZ gene cluster was the most frequently deleted region. Five other cases with azoospermia (4.2%) and two cases with OAT (2.2%) had a chromosomal abnormality, with a total number of seven (3.4%). Including Y chromosome deletions and structural chromosome abnormalities, the rate of genetic abnormalities was 12.5% (26/208) in our patients. On the other hand, 20 men with proven fertility and fathers of five cases with microdeletions were genetically normal. Y chromosome deletions and chromosomal abnormalities were associated with various histological alterations in testis. Sertoli cell-only (SCO) syndrome and maturation arrest predominated in these cases, whereas hypospermatogenesis occurred more frequently in genetically normal patients.

CONCLUSION

Various chromosomal abnormalities and deletions of Y chromosome can cause spermatogenic breakdown resulting in chromosomally derived infertility. All these findings strongly support the recommendation of genetic screening of infertile patients.