{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T10:08:15Z","timestamp":1781863695484,"version":"3.54.5"},"reference-count":53,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2022,9,13]],"date-time":"2022-09-13T00:00:00Z","timestamp":1663027200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Science Foundation","doi-asserted-by":"publisher","award":["19-15-00075"],"award-info":[{"award-number":["19-15-00075"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Male infertility is a multi-factorial and multi-genetic disorder, and the prevalence of male infertility in the world is estimated at 5\u201335%. The search for the causes of male infertility allowed for identifying a number of genetic factors including a single X-linked gene of the androgen receptor (AR), and some of its alleles are assumed to negatively affect male fertility. Our aim was (1) to study the variability of the length of CAG repeats of the AR gene and possible associations in the AR CAG genetic variants with semen quality and reproductive hormone levels in a population-based cohort of men and (2) to estimate distributions of AR CAG repeat alleles and associations with semen parameters in different ethnic subgroups. The cohort of 1324 young male volunteers of different ethnicities (median age 23.0 years) was recruited from the general population of five cities of the Russian Federation, regardless of their fertility status. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B) and trinucleotide (CAG) n repeat polymorphism in exon 1 of the AR gene were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010), serum hormones were measured by enzyme immunoassay, and the AR CAG repeat length was analyzed by direct sequencing of leukocyte DNA. The median AR CAG repeat length in men of our multi-ethnic population was 23 (range 6\u201339). In the entire study population, a significant difference (p \u2264 0.05) was found in the frequency distribution and the mean values for the CAG repeat length between the groups with normal (23.2 \u00b1 3.3) and impaired semen quality (23.9 \u00b1 3.2). Additionally, we demonstrated that the total sperm count, sperm concentration, progressive motility and normal morphology were lower in the category of long CAG repeats (CAG \u2265 25) compared with those in the category of short CAG repeats (CAG \u2264 19); however, hormonal parameters did not differ between the long and short CAG categories, with the exception of estradiol. Significant differences were observed in the AR CAG repeat length between the most common ethnic cohorts of Slavs (Caucasians), Buryats (Asians), and Yakuts (Asians). The Buryats and Yakuts had a higher number of CAG repeats than the Slavs (medians: Slavs\u201423; Buryats\u201424; Yakuts\u201425). The range of alleles differed among ethnicities, with the Slavs having the largest range (7\u201336 repeats, 24 alleles total), the Yakuts having the smallest range (18\u201332 repeats, 14 alleles total) and the Buryats having the middle range (11\u201339 repeats, 20 alleles total). The longer CAG repeats were associated with an impaired semen quality within the Slavic (CAG \u2265 25) and Buryat (CAG \u2265 28) groups, but this effect was not found in Yakuts. Hormonal parameters did not differ between the three CAG repeat categories in men of all ethnic groups. This is the largest Russian study of the distribution of AR CAG repeats and the search for association between length of AR CAG repeat tract and impaired spermatogenesis in men from the general population. Our results confirmed the association of longer CAG repeats with a risk of impaired semen quality, but this association can be modified by ethnic origin. Identification of the number of AR CAG repeats can be an effective tool to assess the risk of male subfertility and the control of androgen hormone therapy of reproductive diseases.<\/jats:p>","DOI":"10.3390\/ijms231810594","type":"journal-article","created":{"date-parts":[[2022,9,13]],"date-time":"2022-09-13T21:06:52Z","timestamp":1663103212000},"page":"10594","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Androgen Receptor Gene CAG Repeat Length Varies and Affects Semen Quality in an Ethnic-Specific Fashion in Young Men from Russia"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7597-9204","authenticated-orcid":false,"given":"Ludmila","family":"Osadchuk","sequence":"first","affiliation":[{"name":"Department of Human Molecular Genetics, Federal Research Center \u2018Institute of Cytology and Genetics\u2019, The Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0929-6832","authenticated-orcid":false,"given":"Gennady","family":"Vasiliev","sequence":"additional","affiliation":[{"name":"Department of Human Molecular Genetics, Federal Research Center \u2018Institute of Cytology and Genetics\u2019, The Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7537-2525","authenticated-orcid":false,"given":"Maxim","family":"Kleshchev","sequence":"additional","affiliation":[{"name":"Department of Human Molecular Genetics, Federal Research Center \u2018Institute of Cytology and Genetics\u2019, The Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander","family":"Osadchuk","sequence":"additional","affiliation":[{"name":"Department of Human Molecular Genetics, Federal Research Center \u2018Institute of Cytology and Genetics\u2019, The Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,9,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"581838","DOI":"10.3389\/fendo.2020.581838","article-title":"The role of genetics and oxidative stress in the etiology of male infertility-a unifying hypothesis?","volume":"11","author":"Aitken","year":"2020","journal-title":"Front. 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