Abstract

Background. Infertility is the failure to conceive after at least one year of unprotected intercourse. It affects approximately 15% of couples. In about 30% of cases male factor infertility can be the result of genetic causes, including chromosome abnormalities.
The aim of the study. To study the prevalence of chromosome abnormalities and chromosomal variants in infertile men in Estonia.
Material and methods. Cytogenetic analyses from the lymphocyte cultures of peripheral blood, using GTG, CBG banding and fluorescence in situ hybridization methods, were performed in 90 infertile men with azoospermia (n = 32) or oligozoospermia (n = 58) referred by andrologists and urologists, and in 30 control fertile men.
Results. The prevalence of chromosomal alterations was high both in infertile men and in the control group (47.8% and 43.3%, respectively). Among them, major chromosomal abnormalities were revealed more frequently (13.4%) in infertile males (15.6% in azoospermics and 12% in oligozoospermics) than in the control group. Autosomal structural abnormalities were detected in 7 patients (7.8%): in one man with  azoospermia (3.1%) and in 6 men with oligozoospermia (10.3%). The most frequent autosome abnormality in infertile men was translocation (5.6%). Numerical sex chromosome abnormalities (karyotype 47,XXY) were found in 5 patients (5.6%): in 4 men with azoospermia (12.5%) and in one man with oligozoospermia (1.7%). The prevalence of chromosomal variants was high both in infertile males and in the control group (37.8% and 43.3%, respectively) but it was almost equal in males with azoospermia and in men with oligozoospermia (40.6% and 36.2%, respectively).
Conclusions. Infertile men in Estonia displayed a high prevalence of chromosome abnormalities, even though they did not have features of genetic disease. Both the numerical abnormalities of sex chromosomes and the structural anomalies of autosomes may cause a variable degree of spermatogenic disturbances. Numerical sex chromosome abnormalities are the cause of more severe impairment of spermatogenesis than autosome structural abnormalities. Therefore, we agree with the authors who suggest that chromosome analyses should be performed routinely in every infertile male, especially before planning an intracytoplasmic sperm injection.