Azoospermia factor microdeletion in infertile men with idiopathic severe oligozoospermia or non-obstructive azoospermia

Objectives: To determine Y-chromosome microdeletion of azoospermia factor (AZF) loci and the concomitant testicular pathology in azoospermic and severely oligozoospermic infertile men. Patients and methods: DNA from blood and semen of 50 azoospermic and severely oligozoospermic infertile men (study group) and 54 healthy fertile men (control group) was investigated for microdeletion in AZF loci, using several Sequence-Tagged Site (STS) markers for AZF. Additionally, testicular biopsies from infertile men were examined to evaluate testicular morphological changes. Results: 22% (11/50) of the patients of the study group had at least one microdeletion in one or more loci of the AZF sub-regions. Sixteen microdeletions were found in the DNA extracted from blood, while 19 microdeletions were found in the DNA extracted from semen. Microdeletions were detected in the 3 AZFb loci in one case, in both AZFb and AZFc loci in another and in two AZFc loci in a third case; 8 cases had sporadic microdeletions in a single locus. Moreover, the incidence of both AZFb and AZFc microdeletions was 14% (DNA from blood) and 16% (DNA from semen), whereas AZFa microdeletions were found in only 2% (DNA from blood) and 4% (DNA from semen) of the patients. The testicular biopsies revealed variable histological changes ranging from hyalinized seminiferous tubules to arrested spermatogenesis. No microdeletion was detected in the control subjects. Conclusion: Y-chromosome microdeletions of the AZF loci are frequently seen in azoospermic and severely oligozoospermic infertile men and are usually associated with impaired spermatogenesis and variable degrees of testicular histological changes.