The cytogenetic aspect of male infertility

Dear Editor Infertility affects approximately 15% of couples worldwide. Within 50% of cases, man provides reproductive function disorders (1). The cause of infertility in men with oligospermia and azoospermia seems to be due to underlying genetic abnormalities (2). Chromosomal abnormalities are one of the causes of human infertility as they interfere with spermatogenesis. The frequency of chromosomal aberrations and specific translocations in infertile men is multiplied by 10 compared with the normal population (3). Hundred patients aged between 26 and 50 years (the middle age 35 years old), oriented by specialized medical structures, are included in our study. All patients were referred for sterility (no spontaneous pregnancy despite >1 year unprotected intercourse). Only couples with infertility primary, in which men had a review of abnormal sperm: azoospermia or severe oligospermia (concentration sperm cells <5×10 6 ml and mobility <40%) were included in the study. 20 metaphases for each patient were analyzed by GTG banding technique (Giemsa Trypsin G bands). In our sample, there were 76 patients (76%) with an ordinary karyotype of which 5 have a known etiology. The most frequent medical history was a mumps orchitis, testicular ectopia, right and left inguinal testicles, or a bilateral varicocele. For patients without obvious etiology, it was important to mention the environmental and other genetic factors unidentified within the limits of the used technique. The chromosome abnormality rate was 24%; the numerical type 21% and structural type 3%. The chromosomal aberrations found in this study, were gonosomal (21/24: 87.5%) and autosomal 3/24: 12.5%). In 64.2% (18/28) of patients the azoospermia was determined by aneuploidy 47, XXY (Figure 1). Subjects 47, XXY (18/100 patients: 18%) had clinical signs or a complete picture mentioning Klinefelter syndrome. Aneuploidy 47, XYY was identified in three patients with the oligoasthénospermia (Figure 2). The Robertsonian translocations 45,XY,der (13)(14) (Figure 3) and reciprocal translocation 46, XY t(3q-10q) (Figure 4) explain oligozoospermia and oligoasthenoteratospermia. These findings are in accordance with those from other surveys and confirm that the XXY aneuploidy is the most frequent chromosomal abnormality in azoospermic individuals. The correlation is established between the karyotypic abnormalities and sperm characteristics. A review of the literature of somatic chromosome investigations in infertile males has shown that 10-15% of azoospermic males and 4-5% of oligozoospermic males have an abnormal karyotype. In the first group, sex chromosome abnormalities predominate (mainly 47,XXY), whereas in the latter, autosome anomalies (i.e. Robertsonian and reciprocal translocations) are …