TCAS 10. Genetic testing of infertile males with nonobstructive azoospermia or severe Oligozoospermia In Taiwan

Chromosomal abnormality is one of the causes of male infertility. It is seen more frequently in azoospermic, and severe oligozoopsermic patients with unknown etiology. These patients were usually candidates of assisted reproduction techniques (ART). In present study, we analyzed the karyotyping patterns of infertile males with azoospermia or severe oligozoospermia, and their associated clinical characteristics. Besides, phenotypic effects of the gr/gr partial azoospermia factor (AZF) c deletion were also evaluated to assess the clinical characteristics of subfertile Taiwanese men with the gr/gr deletion.

We retrospectively reviewed patients' log of 370 infertile males with nonobstructive azoospermia (NOA), or severe oligozoospermia from January 2004 to March 2011. All patients received classic karyotyping with peripheral white cell culture, and the Y chromosome microdeletion testing was also performed with multiplex PCR methods. We collected physical examination findings,sperm count, hormone profile, and the outcome of microdissection testicular sperm extraction (MDTESE) regarding gr/gr status and analyzed with Chi-square and Fisher's exact tests. Normozoospermia, oligozoospermia, and severe oligospermia were defined as ≥ 20 million/mL, 5 to 20 million/mL, and < 5 million/mL respectively.

Seventy (18.9%) out of the 370 men were identified to have abnormal karyotyping other than 46 XY. Among these 70 patients, 48 (68.6%) were with NOA, 14 (20%) were oligozoospermia, 4 (10.3%) were ductal obstruction, 1 (10%) was normal semen analysis. Among all azoospermic men, those with abnormal karyotyping had significantly higher levels in FSH (P=0.0007) and LH (P<0.0001); lower in prolactin (P=0.047) and testosterone (P<0.0001), and smaller testes volumes (P<0.0001). Among all patients with abnormal karyotyping, men with NOA had significantly higher FSH (P< 0.0001), higher LH (P=0.0004), lower prolactin (P=0.03) levels, and smaller testes volumes (P=0.0001), comparing with oligozoospermic and obstructive azoospermic patients. There was no difference among three groups when it comes to serum testosterone (P=0.085). 47 XXY was the most common abnormal karyotype among azoospermic patients (n=31, 66.0%), followed by sex chromosome mosaicism (n=5, 10.4%) and other sex chromosome abnormalities (n= 4, 8.3%). Sex chromosome anomalies were identified in 5 patients (35.7%), and inversion was associated with 4 patients (28.6%), especially inv(9) (21.4%). Der (13,14)(10p, 10q) was noticed in 2 patients (14.3%). In 25 patients with concomitant varicoceles, 6 have mosaic sex chromosome karyotyping (24%), 20% patients have abnormal karyotyping involving chromosome 9 (inv(9) in 3 patients, t(Y, 9) in 1 patient, and t(5, 9) in 1 patient), and 12% were Klinefelter syndrome. While among the 27 infertile men with gr/gr deletions, 12 had azoospermia (5.5% of 217 azoospermia), 6 had severe oligozoospermia (8.5% of 71), 5 had oligozoospermia (13.2% of 38), and 3 had normozoospermia (7.7% of 39). The percentage of azoospermia/severe oligozoospermia/oligozoospermia/normozoospermia in patients with gr/gr deletion was 11.5%/19.2%/23.1%/46.2%, respectively. A gr/gr deletion correlated well with greater amount of sperm production. The gr/gr deletion rate was lowest in men with azoospermia and was highest in those with oligozoospermia (P=0.031). MD-TESE was done in 4 azoospermic men with gr/gr deletion but none were found to have sperm. The average sperm retrieval rate of MD-TESE in our institute was 42.9% for the past five years.

The high incidence of chromosomal anomalies in infertile males with NOA suggests the need for routine genetic testing and counseling in these patients, especially when certain hormonal characteristics were reported. Specific cytogenetic abnormalities or chromosome loci might be worth of further investigation to discover their possible relationship with infertility. In our limited data, gr/gr deletion seemed to be a poor prognostic factor for successful sperm retrieval, although we didn't confirm gr/gr deletion to predict impaired sperm production in general population in Taiwan. Despite the established modulatory impact of the gr/gr deletion on sperm production in some populations at this time, the clinical value of testing infertile Taiwanese men for the gr/gr deletion is not clear yet.