Chromosomal studies in infertile men with oligozoospermia & non-obstructive azoospermia

Abstract

Background & objective: Chromosomal anomalies have been postulated to be as one of the principal genetic factors in male infertility. Cytogenetic evaluation of men with severely compromised semen parameters reveals an increased incidence of chromosomal aberrations when compared with the normal population. The objective of this study was to determine the chromosomal constitution and sperm characteristics among Indian males with severe male factor infertility.

Methods: In this prospective study we investigated 88 infertile men (42 men with azoospermia and 46 men with sperm count <5 x 10(6) million/ml) prior to intracytoplasmic sperm injection (ICSI) treatment. Karyoptying was performed on peripheral blood lymphocytes according to standard methods. Polymerase chain reaction (PCR) was performed to screen the microdeletions in the AZF region of the Y chromosome.

Results: Constitutional chromosome abnormalities were identified in 14.3 per cent of azoospermic and 6.5 per cent of oligozoospermic men, with an overall rate of 10.2 per cent. Chromosomal abnormalities included gonosomal aberrations in 5 cases. Robertsonian translocation in one, trisomy 7 mosaicism in one case, deletion in chromosome 16 in one, and a marker chromosome in one case. Chromosome variants were observed in 33 (37.5%) subjects. Yqh- was the most frequent variant in sex chromosomes and increased length in heterochromatin and satellites were observed in autosomal chromosomes.

Interpretation & conclusion: The high rate of chromosomal anomalies among infertile men strongly suggests the need for routine cytogenetic analysis prior to employment of assisted reproduction techniques. In addition, meticulous follow-up of babies born after ICSI, especially male offsprings, is necessary.