CAG repeat length in the androgen receptor gene is enhanced in patients with idiopathic azoospermia

No Association of the CAG Repeat Length in Exon 1 of the Androgen Receptor Gene with Idiopathic Infertility in Turkish Men: Implications and Literature Review

“…The results from analyses of reproductive hormones with elevated LH and FSH, and normal or low testosterone levels were suggestive of partial impairment of testicular function and were in agreement with results from previously published studies (Dowsing et al 1999;Yoshida et al 1999). No statistically significant relationship between the length of the CAG repeat of the AR gene and idiopathic impaired sperm production was observed in the Turkish population studied (p = 0.84, Table 2).…”

“…Based on this information, in a study of exon 1 of the AR gene in infertile males of predominantly (60%) Chinese ethnic origin it was found that expansion of the trinucleotide (CAG) repeat and thus of the polyglutamine tract could be associated with increased risk of impaired spermatogenesis (Tut et al 1997). This finding was then corroborated by several studies from a variety of different ethnic populations including Japanese, Caucasian, North American, French, Israeli, Taiwanese and Spanish (Yoshida et al 1999;Dowsing et al 1999;Mifsud et al 2001;Wallerand et al 2001;Patrizio et al 2001;Madgar et al 2002;Pan et al 2002;Casella et al 2003;Asatiani et al 2003;Mengual et al 2003). However, several others, who have investigated Swedish, Belgian, German, Japanese, Danish, Dutch, Indian, Greek, New Zealander, Finish, Hong Kong Chinese and Italian populations were unable to demonstrate an association (Giwercman et al 1998;Legius et al 1999;Hiort et al 1999;Dadze et al 2000;Sasagawa et al 2000Sasagawa et al , 2001Von Eckardstein et al 2001;Yu and Handelsman 2001;Kukuvitis et al 2002;Rajpert-De Meyts et al 2002;Van Golde et al 2002;Thangaraj et al 2002;Dhillon and Husain 2003;Erasmuson et al 2003;Lund et al 2003;Tse et al 2003;Ferlin et al 2004).…”

“…An extensive literature search supported this finding and the hypothesis that ethnic background plays a major role in terms of CAG repeat number and its association with idiopathic male infertility (Table 3). While it is possible to explain the differences in results observed in several different populations studied with this statement, it is interesting that 3 studies originated from the same population, i.e., Japanese men, reported opposing results to each other (Yoshida et al 1999;Komori et al 1999;Sasagawa et al 2001). Yoshida et al (1999) examined 41 azoospermic Japanese men and reported the mean CAG repeat length as 26.5 ± 3.5 (range 20-34) in comparison to 23.5 ± 2.9 (range 17-30) CAG repeats in fertile controls (p = 0.0013).…”

“…While it is possible to explain the differences in results observed in several different populations studied with this statement, it is interesting that 3 studies originated from the same population, i.e., Japanese men, reported opposing results to each other (Yoshida et al 1999;Komori et al 1999;Sasagawa et al 2001). Yoshida et al (1999) examined 41 azoospermic Japanese men and reported the mean CAG repeat length as 26.5 ± 3.5 (range 20-34) in comparison to 23.5 ± 2.9 (range 17-30) CAG repeats in fertile controls (p = 0.0013). Komori et al (1999) examined 59 Japanese infertile men with oligozoospermia in general and found that the mean CAG repeat length in infertile men did not differ significantly from that of fertile controls (21.2 ± 4.2, range 14-32, vs 21.4 ± 3.5, range 16-31, respectively), however, they reported that the frequency of having CAG repeats (< 16) was significantly higher in infertile men (p < 0.05).…”

“…decade (Tut et al 1997;Yoshida et al 1999;Dowsing et al 1999;Mifsud et al 2001;Patrizio et al 2001;Wallerand et al 2001;Madgar et al 2002;Pan et al 2002;Asatiani et al 2003;Casella et al 2003;Mengual et al 2003), whereas several others were unable to demonstrate an association (Giwercman et al 1998;Hiort et al 1999;Legius et al 1999;Dadze et al 2000;Sasagawa et al 2000Sasagawa et al , 2001Von Eckardstein et al 2001;Yu and Handelsman 2001;Rajpert-De Meyts et al 2002;Van Golde et al 2002;Thangaraj et al 2002;Kukuvitis et al 2002;Erasmuson et al 2003;Dhillon and Husain 2003;Lund et al 2003;Tse et al 2003;Ferlin et al 2004). Thus, the ethnic background of the population studied may play an important role in the correlation between CAG repeat length and male infertility.…”