Study of the influence of androgen receptor gene CAG polymorphism and the parental origin of the additional X chromosome on clinical and laboratory parameters in adolescents with Klinefelter syndrome

   Introduction. Klinefelter syndrome (KS) is a sex chromosome abnormality characterized by high prevalence in various populations, hypergonadotropic hypogonadism, male infertility, pronounced clinical variability of symptoms and commonly late diagnosis. The causes of phenotypic variability of KS, including the influence of genetic, epigenetic and environment factors on it, is still not well understood.

   Aim: evaluation of the CAG polymorphism of androgen receptor (AR) gene and the parental origin of the X chromosomes on clinical and laboratory parameters in Klinefelter syndrome patients.

   Methods. We examined 34 KS patients 5-18 years of age with following karyotypes: 47,XXY (n = 32); 48,XXYY (n = 1) и mos 47,ХХY[22]/46,XY[8] (n = 1). Two patients were monozygotic twins, the other patients were unrelated. Parental origin of the X chromosomes was determined by genotyping for (CAG)n polymorphism of the AR gene and (GAAA)n polymorphism, near to the RP2 gene, in patients and parents. The influence of the origin of the additional X chromosome and CAG-repeats of AR gene on the clinical and laboratory parameters was assessed in 22 adolescents with a karyotype 47,XXY, who had reached the Tanner stage of sexual development ≥2, and not received testosterone replacement therapy at the time of examination.

   Results. The number of CAG repeats of the AR gene in KS patients was ranged from 16 to 27, and 22 alleles (32.4%) contained from 20 or 21 repeats. According to CAG-repeats, a group of 22 adolescents with KS was divided into 3 subgroups: carriers of “short” alleles ((CAG) n ≤ 19; 6 patients), “medium” alleles ((CAG) n = 20–25; 12 patients) and “long” alleles ((CAG)n ≥ 26; 4 patients) alleles. Comparative analysis of anthropometric data (SDS of height and BMI, ΔSDS of body segments) did not reveal statistically significant differences between subgroups. In the group of carriers of “long” alleles, higher levels of testosterone and insulin and a larger testicular volume were noted compared to carriers of “medium” and “short” alleles. The study groups also did not differ in the levels of gonadotropins (LH, FSH) and metabolic profile indicators (total cholesterol, LDL, HDL, TG). The parental origin of the additional X chromosome was established in 33 patients, of which 22 (67 %) patients had maternal origin (Xm), and 11 (33 %) individuals had paternal origin (Xp). Analysis of the influence of the origin of the X chromosome on anthropometric indicators, hormonal and lipid profiles in 22 adolescents selected for the study (additional Xm, n=15; additional Xp, n=7) did not reveal statistically significant differences between the subgroups. No significant influence of the parental origin of the additional X chromosome and the CAG polymorphism of the androgen receptor gene on clinical and hormonal-metabolic parameters in our sample of KS patients, was found.

1. Bojesen A., Juul S., Gravholt C. et al. Prenatal and postnatal prevalence of Klinefelter syndrome: a national registry study. J Clin Endocrinol Metab, 2003; 88(2):622-626. doi: 10.1210/jc.2002-021491.

2. Herlihy A., Halliday J., Cock M. et al. The prevalence and diagnosis rates of Klinefelter syndrome: an Australian comparison. Med J Aust, 2011; 194:24–28. doi: 10.5694/j.1326-5377.2011.tb04141.x

3. Zitzmann M., Bongers R., Werler S. et al. Gene expression patterns in relation to the clinical phenotype in Klinefelter syndrome. J Clin Endocrinol Metab, 2015; 100(3): 518-523. doi: 10.1210/jc.2014-2780.

4. Zhang X., Hong D., Ma S. et al. Integrated functional genomic analyses of Klinefelter and Turner syndromes reveal global network effects of altered X chromosome dosage. Proc Natl Acad Sci USA. 2020;117(9):4864-4873. doi: 10.1073/pnas.1910003117

5. Navarro-Cobos M.J., Balaton B.P., Brown C.J. Genes that escape from X-chromosome inactivation: Potential contributors to Klinefelter syndrome. Am J Med Genet C Semin Med Genet. 2020;184(2):226-238. doi: 10.1002/ajmg.c.31800.

6. Thomas N., Hassold T. Aberrant recombination and the origin of Klinefelter syndrome. Hum Reprod Update, 2003; 9(4):309-17. doi: 10.1093/humupd/dmg028.

7. Lorda-Sanchez I., Binkert F., Maechler M. et al. Reduced recombination and paternal age effect in Klinefelter syndrome. Hum Genet, 1992; 89(5):524-30. doi: 10.1007/BF00219178.

8. Vorona E., Zitzmann M., Gromoll J. et al. Clinical, endocrinological, and epigenetic features of the 46,XX male syndrome, compared with 47,XXY Klinefelter patients. J Clin Endocrinol Metab. 2007;92(9):3458-3465. doi: 10.1210/jc.2007-0447.

9. Chang S., Skakkebæk A., Trolle C. et al. Anthropometry in Klinefelter syndrome-multifactorial influences due to CAG length, testosterone treatment and possibly intrauterine hypogonadism. J Clin Endocrinol Metab. 2015;100(3):E508-517. doi: 10.1210/jc.2014-2834.

10. Shchagina O.A., Mironovich O.L., Zabnenkova V.V., Galeeva N.M., Bliznetz E.A., Chuchrova A.L., Polyakov A.V. Ekspansiya CAG-povtora v ekzone 1 gena AR u bol’nykh spinal’noy amiotrofiyey [CAG expansion in exon 1 of the AR gene in Russian spinal atrophy patients]. Meditsinskaya genetika [Medical Genetics]. 2017;16(9):31-36. (In Russ.)

11. Chernykh V.B., Rudneva S.A., Sorokina T.M., Shileyko L.V., Ostroumova T.V., Ermolaeva S.A., Kurilo L.F., Ryzhkova O.P., Bliznets E.A., Chukhrova A.L., Polyakov A.V. Vliyaniye SAG-polimorfizma gena androgenovogo retseptora (AR) na spermatogenez u muzhchin s besplodiyem [An influence of androgen receptor (AR) gene СAG-polymorphism on spermatogenesis in infertile men]. Andrologiya i genital’naya khirurgiya [Andrology and Genital Surgery]. 2015;16(4):55-61. (In Russ.) URL: https://cyberleninka.ru/article/n/vliyanie-sag-polimorfizma-gena-androgenovogo-retseptora-ar-na-spermatogenez-u-muzhchin-s-besplodiem?ysclid=ltebdr9hr9448399114.

12. Melikyan, L.P., Bliznetz, E.A., Polyakov, A.V. et al. Polymorphism of CAG Repeats in Exon 1 of the Androgen Receptor Gene in Russian Men with Various Forms of Pathozoospermia. Russ J Genet 56, 1000–1005 (2020). doi: 10.1134/S1022795420080104

13. Tanner J.M., Whitehouse R.H. Clinical longitudinal standards for height, weight, height velocity, weight velocity, and stages of puberty. Arch Dis Child. 1976 Mar; 51(3):170-9. doi: 10.1136/adc.51.3.170.

14. Cole T.J., Bellizzi M.C., Flegal K.M., et al. Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ. 2000. 320:1240–1243. doi: 10.1136/bmj.320.7244.1240.

15. Marshall W.A., Tanner J.M. Variations in the Pattern of Pubertal Changes in Boys. Arch Dis Child, 1970; 45 (239): 13–23.

16. Mikhaylenko D.S., Sobol I.Y., Safronova N.Y., Simonova O.A., Efremov E.A., Efremov G.D., Alekseev B.Y., Kaprin A.D., Nemtsova M.V. Chastota vyyavleniya deletsiy AZF, mutatsiy CFTR i dlinnykh alleley CAG-povtora AR pri pervichnoy laboratornoy diagnostike v geterogennoy gruppe patsiyentov s muzhskim besplodiyem [The incidence of AZF deletions, CFTR mutations and long alleles of the ar CAG repeats during the primary laboratory diagnostics in a heterogeneous group of infertily men]. Urologiia [Urology] 2019; 2: 101-107. (In Russ.)

17. Wikström A.M., Painter J.N., Raivio T., Aittomäki K., Dunkel L. Genetic features of the X chromosome affect pubertal development and testicular degeneration in adolescent boys with Klinefelter syndrome. Clin Endocrinol (Oxf). 2006;65(1):92-97. doi: 10.1111/j.1365-2265.2006.02554.x

18. Ross J.L., Roeltgen D.P., Stefanatos G. et al. Cognitive and motor development during childhood in boys with Klinefelter syndrome. Am J Med Genet A. 2008; 146A(6):708–719. doi: 10.1002/ajmg.a.32232

19. Zeger M.P, Zinn A.R, Lahlou N. et al. Effect of ascertainment and genetic features on the phenotype of Klinefelter syndrome. J Pediatr. 2008; 152(5):716–722. doi: 10.1016/j.jpeds.2007.10.019

20. Skakkebaek A., Bojesen A., Kristensen M.K. et al. Neuropsychology and brain morphology in Klinefelter syndrome - the impact of genetics. Andrology. 2014; 2(4):632–640. doi:10.1111/j.2047-2927.2014.00229.x

21. Stemkens D., Roza T., Verrij L. et al. Is there an influence of X-chromosomal imprinting on the phenotype in Klinefelter syndrome? A clinical and molecular genetic study of 61 cases. Clin Genet 2006; 70(1): 43–48. doi: 10.1111/j.1399-0004.2006.00635.x

22. Bruining H., Swaab H., Kas M., van Engeland H. Psychiatric characteristics in a self-selected sample of boys with Klinefelter syndrome. Pediatrics 2009; 123(5):865–870. doi: 10.1542/peds.2008-1954

23. Zitzmann M., Depenbusch M., Gromoll J. et al. X-chromosome inactivation patterns and androgen receptor functionality influence phenotype and social characteristics as well as pharmacogenetics of testosterone therapy in Klinefelter patients. J Clin Endocrinol Metab, 2004; 89(12): 6208–6217. doi: 10.1210/jc.2004-1424.

24. Ferlin A., Schipilliti M., Vinanzi C. et al. Bone mass in subjects with Klinefelter syndrome: role of testosterone levels and androgen receptor gene CAG polymorphism. J Clin Endocrinol Metab, 2011;96(4):739–745. doi: 10.1210/jc.2010-1878.

25. Bojesen A., Hertz J.M., Gravholt C.H. Genotype and phenotype in Klinefelter syndrome - impact of androgen receptor polymorphism and skewed X inactivation. Int J Androl, 2011; 34(6 Pt 2):e642–648. doi: 10.1111/j.1365-2605.2011.01223.x

26. Rajpert-De Meyts E., Leffers H., Petersen J.H. et al. CAG repeat length in androgen-receptor gene and reproductive variables in fertile and infertile men. Lancet 2002;359(9300):44–46. doi: 10.1016/s0140-6736(02)07280-x

27. Osadchuk L., Vasiliev G., Kleshchev M., Osadchuk A. Androgen Receptor Gene CAG Repeat Length Varies and Affects Semen Quality in an Ethnic-Specific Fashion in Young Men from Russia. Int J Mol Sci. 2022 Sep 13;23(18):10594. doi: 10.3390/ijms231810594.

28. Foresta C., Caretta N., Palego P. et al. Reduced artery diameters in Klinefelter syndrome. Int J Androl 2012; 35(5): 720–725. doi: 10.1111/j.1365-2605.2012.01269.x

29. Benaiges D., Pedro-Botet J., Hernández E., Tarragón S., Chillarón J.J., Flores Le-Roux J.A. Different clinical presentation of Klinefelter’s syndrome in monozygotic twins. Andrologia. 2015;47(1):116–120. doi: 10.1111/and.12219

30. Karibe J., Kuroda S., Saito T., Ishibashi Y., Usui K., Takeshima T., Komeya M., Yumura Y. Monozygotic adult twins with nonmosaic Klinefelter syndrome with different results of sperm retrieval. Andrologia. 2022;54(1):e14266. doi: 10.1111/and.14266