The low frequency of Y chromosome microdeletions in subfertile males in a Sinhalese population of Sri Lanka

Prevalence of Y chromosome microdeletion in azoospermia factor subregions among infertile men from West Bengal, India

Background

Etiology of male infertility is intriguing and Y chromosome microdeletion within azoospermia factor (AZF) sub‐regions is considered major cause. We conducted a screening for Y chromosome microdeletion in an infertile male cohort from West Bengal, India to characterize Y chromosome microdeletion among infertile men.

Methods

We recruited case subjects that were categorized on the basis of sperm count as azoospermia (N = 63), severe oligozoospermia (N = 38), and oligozoospermia (N = 17) and compared them with age, demography, and ethnicity matched healthy proven fertile control males (N = 84). Sequence Tagged Site makers and polymerase chain reaction based profiling of Y chromosome was done for AZF region and SRY for cases and controls.

Results

We scored 16.1% of cases (19 out of 118) that bear one or more microdeletions in the studied loci and none among the controls. The aberrations were more frequent among azoospermic males (17 of 19) than in severe oligozoospermic subjects (2 of 19).

Conclusion

Our study provides the results of screening of the largest Bengali infertile men sample genotyped with the maximum number of STS markers spanning the entire length of Y chromosome long arm. Y chromosome microdeletion is a significant genetic etiology of infertility among Bengali men.

Correlation of genetic results with testicular histology, hormones and sperm retrieval in nonobstructive azoospermia patients with testis biopsy

To investigate the frequency and types of genetic results in different testicular histology of patients with nonobstructive azoospermia (NOA), and correlated with hormones and sperm retrieval (SR), a retrospective study was conducted in 286 Chinese NOA patients who underwent testis biopsy and 100 age-matched fertile men as the control group. Chromosome karyotype analyses were performed by the peripheral blood chromosome G-band detection method. Screening of Y chromosome microdeletions of azoospermia factor (AZF) region was performed by polymerase chain reaction (PCR) amplification of 11 sequence-tagged sites (STS). The serum levels of follicle-stimulating hormone, luteinising hormone and testosterone (T) and the appearance of scrotal ultrasound were also obtained. In 286 cases of NOA, 14.3% were found to have chromosomal alterations. The incidence of chromosomal abnormality was 2.8%. Sex chromosomal abnormalities were seen in six cases (four cases of Klinefelter's syndrome (47, XXY) and two cases of mosaics). The incidence of polymorphic chromosomal variants was 3% in the normal group and 11.5% in the NOA group. In total, 15.7% of NOA patients were found to have AZF microdeletions and AZF (c + d) was the most frequent one. The results of hormone and SR were found to be significantly different among all testicular histological types, whereas no significant differences were found when it comes to genetic alterations. It is concluded that the rate of cytogenetic alterations was high in NOA patients. So screening for chromosomal alterations and AZF microdeletions would add useful information for genetic counselling in NOA patients with testis biopsy and avoid vertical transmission of genetic defects by assisted reproductive technology.

Genetic Risk of Azoospermia Factor (AZF) Microdeletions in Idiopathic Cases of Azoospermia and Oligozoospermia in Central Indian Population

BACKGROUND

Genetic factors cause about 15% of male infertility. Azoospermia factors (AZFa, AZFb, and AZFc) present on Yq are most important for spermatogenesis. We have made an attempt to evaluate the frequencies of microdeletions of AZFa, AZFb, AZFc in idiopathic cases of azoospermia and oligozoospermia from central Indian population.

MATERIALS AND METHODS

We have analyzed a total of 156 subjects (95 oligozoospermia and 61 azoospermia) & 50 control subjects. DNA samples were analyzed for microdeletions of Y chromosome by PCR-screening of 18 sequences-tagged-site (STS) markers from different region of the AZF on Yq and SRY on Yp.

RESULTS

Out of 156 cases analyzed, 13 (8.33%) subjects (8 azoospermia and 5 oligozoospermia) showed partial deletion of AZF regions, of which deletion in AZFc region was the most common (84.6%) followed by AZFb (15.4%) and AZFa (15.4%). The sites and sizes of deletions varied among patients. Histological study of the testicular tissue of the available subjects, who showed microdeletions of Y chromosome, showed spermatogenic arrest at different stages. The frequency of Y chromosome microdeletion in our subjects was 8.33%.

CONCLUSION

Some Indian studies reported low frequencies of microdeletions than that of our result. We suggest that the frequency of deletions may be affected by the involvement of different genetic factors, ethnic population and different geographical regions. PCR based Y chromosome screening for microdeletions will be useful and great help to infertility clinics for genetic counselling and assisted reproduction.