1. Abreu AP, Kaiser UB. Pubertal development and regulation. Lancet Diabetes Endocrinol. 2016; 4:254–64.
2. Grumbach MM. The neuroendocrinology of human puberty revisited. Horm Res. 2002; 57 Suppl 2:2–14.
3. Palmert MR, Dunkel L. Clinical practice. Delayed puberty. N Engl J Med. 2012; 366:443–53.
4. Markosyan R. Patients with disorders of sex development. Ann Pediatr Endocrinol Metab. 2021; 26:74–9.
5. Thirumalai A, Anawalt BD. Epidemiology of male hypogonadism. Endocrinol Metab Clin North Am. 2022; 51:1–27.
6. Bozzola M, Bozzola E, Montalbano C, Stamati FA, Ferrara P, Villani A. Delayed puberty versus hypogonadism: a challenge for the pediatrician. Ann Pediatr Endocrinol Metab. 2018; 23:57–61.
7. Xie Q, Kang Y, Zhang C, Xie Y, Wang C, Liu J, et al. The role of kisspeptin in the control of the hypothalamicpituitary-gonadal axis and reproduction. Front Endocrinol (Lausanne). 2022; 13:925206.
8. Cho HJ, Shan Y, Whittington NC, Wray S. Nasal placode development, GnRH neuronal migration and Kallmann syndrome. Front Cell Dev Biol. 2019; 7:121.
9. Renault CH, Aksglaede L, Wøjdemann D, Hansen AB, Jensen RB, Juul A. Minipuberty of human infancy - A window of opportunity to evaluate hypogonadism and differences of sex development? Ann Pediatr Endocrinol Metab. 2020; 25:84–91.
10. Spaziani M, Tarantino C, Tahani N, Gianfrilli D, Sbardella E, Lenzi A, et al. Hypothalamo-pituitary axis and puberty. Mol Cell Endocrinol. 2021; 520:111094.
11. Balasubramanian R, Dwyer A, Seminara SB, Pitteloud N, Kaiser UB, Crowley WF Jr. Human GnRH deficiency: a unique disease model to unravel the ontogeny of GnRH neurons. Neuroendocrinology. 2010; 92:81–99.
12. O'Shaughnessy PJ, Monteiro A, Verhoeven G, De Gendt K, Abel MH. Effect of FSH on testicular morphology and spermatogenesis in gonadotrophin-deficient hypogonadal mice lacking androgen receptors. Reproduction. 2010; 139:177–84.
13. Rastrelli G, Corona G, Mannucci E, Maggi M. Factors affecting spermatogenesis upon gonadotropin-replacement therapy: a meta-analytic study. Andrology. 2014; 2:794–808.
14. Prior M, Stewart J, McEleny K, Dwyer AA, Quinton R. Fertility induction in hypogonadotropic hypogonadal men. Clin Endocrinol (Oxf). 2018; 89:712–8.
15. Walker WH, Cheng J. FSH and testosterone signaling in Sertoli cells. Reproduction. 2005; 130:15–28.
16. Zacharin M. Pubertal induction in hypogonadism: current approaches including use of gonadotrophins. Best Pract Res Clin Endocrinol Metab. 2015; 29:367–83.
17. Lenzi A, Balercia G, Bellastella A, Colao A, Fabbri A, Foresta C, et al. Epidemiology, diagnosis, and treatment of male hypogonadotropic hypogonadism. J Endocrinol Invest. 2009; 32:934–8.
18. Young J, Xu C, Papadakis GE, Acierno JS, Maione L, Hietamäki J, et al. Clinical management of congenital hypogonadotropic hypogonadism. Endocr Rev. 2019; 40:669–710.
19. Palmert MR, Hirschhorn JN. Genetic approaches to stature, pubertal timing, and other complex traits. Mol Genet Metab. 2003; 80:1–10.
20. Stamou MI, Varnavas P, Kentrou M, Adamidou F, Voutetakis A, Jing J, et al. Isolated GNRH deficiency: genotypic and phenotypic characteristics of the genetically heterogeneous Greek population. Eur J Endocrinol. 2017; 176:L1–5.
21. Gach A, Pinkier I, Sałacińska K, Szarras-Czapnik M, Salachna D, Kucińska A, et al. Identification of gene variants in a cohort of hypogonadotropic hypogonadism: Diagnostic utility of custom NGS panel and WES in unravelling genetic complexity of the disease. Mol Cell Endocrinol. 2020; 517:110968.
22. Stamou MI, Cox KH, Crowley WF Jr. Discovering genes essential to the hypothalamic regulation of human reproduction using a human disease model: adjusting to life in the "-omics" era. Endocr Rev. 2015; 36:603–21.
23. Choi HS, Kwon A, Chae HW, Suh J, Song KC, Lee JS, et al. Identification of a novel point mutation in DAX-1 gene in a patient with adrenal hypoplasia congenita. Ann Pediatr Endocrinol Metab. 2021; 26:126–9.
24. Choe J, Kim JH, Kim YA, Lee J. Dizygotic twin sisters with normosmic idiopathic hypogonadotropic hypogonadism caused by an FGFR1 gene variant. Ann Pediatr Endocrinol Metab. 2020; 25:192–7.
25. Stamou MI, Georgopoulos NA. Kallmann syndrome: phenotype and genotype of hypogonadotropic hypogonadism. Metabolism. 2018; 86:124–34.
26. Topaloglu AK, Kotan LD. Genetics of hypogonadotropic hypogonadism. Endocr Dev. 2016; 29:36–49.
27. Bianco SD, Kaiser UB. The genetic and molecular basis of idiopathic hypogonadotropic hypogonadism. Nat Rev Endocrinol. 2009; 5:569–76.
28. Cariboni A, Balasubramanian R. Kallmann syndrome and idiopathic hypogonadotropic hypogonadism: the role of semaphorin signaling on GnRH neurons. Handb Clin Neurol. 2021; 182:307–15.
29. Maggi R, Cariboni AM, Marelli MM, Moretti RM, Andrè V, Marzagalli M, et al. GnRH and GnRH receptors in the pathophysiology of the human female reproductive system. Hum Reprod Update. 2016; 22:358–81.
30. Pitteloud N, Durrani S, Raivio T, Sykiotis GP. Complex genetics in idiopathic hypogonadotropic hypogonadism. Front Horm Res. 2010; 39:142–53.
31. Main KM, Schmidt IM, Toppari J, Skakkebaek NE. Early postnatal treatment of hypogonadotropic hypogonadism with recombinant human FSH and LH. Eur J Endocrinol. 2002; 146:75–9.
32. Bougnères P, François M, Pantalone L, Rodrigue D, Bouvattier C, Demesteere E, et al. Effects of an early postnatal treatment of hypogonadotropic hypogonadism with a continuous subcutaneous infusion of recombinant follicle-stimulating hormone and luteinizing hormone. J Clin Endocrinol Metab. 2008; 93:2202–5.
33. Stoupa A, Samara-Boustani D, Flechtner I, Pinto G, Jourdon I, González-Briceño L, et al. Efficacy and safety of continuous subcutaneous infusion of recombinant human gonadotropins for congenital micropenis during early infancy. Horm Res Paediatr. 2017; 87:103–10.
34. Jayasena CN, Anderson RA, Llahana S, Barth JH, MacKenzie F, Wilkes S, et al. Society for Endocrinology guidelines for testosterone replacement therapy in male hypogonadism. Clin Endocrinol (Oxf). 2022; 96:200–19.
35. Bhasin S, Brito JP, Cunningham GR, Hayes FJ, Hodis HN, Matsumoto AM, et al. Testosterone therapy in men with hypogonadism: an endocrine society clinical practice guideline. J Clin Endocrinol Metab. 2018; 103:1715–44.
36. Warne DW, Decosterd G, Okada H, Yano Y, Koide N, Howles CM. A combined analysis of data to identify predictive factors for spermatogenesis in men with hypogonadotropic hypogonadism treated with recombinant human folliclestimulating hormone and human chorionic gonadotropin. Fertil Steril. 2009; 92:594–604.
37. Liu PY, Baker HW, Jayadev V, Zacharin M, Conway AJ, Handelsman DJ. Induction of spermatogenesis and fertility during gonadotropin treatment of gonadotropin-deficient infertile men: predictors of fertility outcome. J Clin Endocrinol Metab. 2009; 94:801–8.
38. Miyagawa Y, Tsujimura A, Matsumiya K, Takao T, Tohda A, Koga M, et al. Outcome of gonadotropin therapy for male hypogonadotropic hypogonadism at university affiliated male infertility centers: a 30-year retrospective study. J Urol. 2005; 173:2072–5.
39. Pitteloud N, Hayes FJ, Dwyer A, Boepple PA, Lee H, Crowley WF Jr. Predictors of outcome of long-term GnRH therapy in men with idiopathic hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 2002; 87:4128–36.
40. Burris AS, Rodbard HW, Winters SJ, Sherins RJ. Gonadotropin therapy in men with isolated hypogonadotropic hypogonadism: the response to human chorionic gonadotropin is predicted by initial testicular size. J Clin Endocrinol Metab. 1988; 66:1144–51.
41. Delemarre-Van de Waal HA, Odink RJ. Pulsatile GnRH treatment in boys and girls with idiopathic hypogonadotrophic hypogonadism. Hum Reprod. 1993; 8 Suppl 2:180–3.
42. Delemarre-Van de Waal HA. Induction of testicular growth and spermatogenesis by pulsatile, intravenous administration of gonadotrophin-releasing hormone in patients with hypogonadotrophic hypogonadism. Clin Endocrinol (Oxf). 1993; 38:473–80.
43. Hoffman AR, Crowley WF Jr. Induction of puberty in men by long-term pulsatile administration of lowdose gonadotropin-releasing hormone. N Engl J Med. 1982; 307:1237–41.
44. Wei C, Long G, Zhang Y, Wang T, Wang S, Liu J, et al. Spermatogenesis of male patients with congenital hypogonadotropic hypogonadism receiving pulsatile gonadotropin-releasing hormone therapy versus gonadotropin therapy: a systematic review and meta-analysis. World J Mens Health. 2021; 39:654–65.
45. Swee DS, Quinton R. Managing congenital hypogonadotrophic hypogonadism: a contemporary approach directed at optimizing fertility and long-term outcomes in males. Ther Adv Endocrinol Metab. 2019; 10:2042018819826889.
46. Dwyer AA, Raivio T, Pitteloud N. Gonadotrophin replacement for induction of fertility in hypogonadal men. Best Pract Res Clin Endocrinol Metab. 2015; 29:91–103.
47. Anderson RC, Newton CL, Anderson RA, Millar RP. Gonadotropins and their analogs: current and potential clinical applications. Endocr Rev. 2018; 39:911–37.
48. Han TS, Bouloux PM. What is the optimal therapy for young males with hypogonadotropic hypogonadism? Clin Endocrinol (Oxf). 2010; 72:731–7.
49. Casarini L, Crépieux P, Reiter E, Lazzaretti C, Paradiso E, Rochira V, et al. FSH for the treatment of male infertility. Int J Mol Sci. 2020; 21.
50. Dwyer AA, Sykiotis GP, Hayes FJ, Boepple PA, Lee H, Loughlin KR, et al. Trial of recombinant follicle-stimulating hormone pretreatment for GnRH-induced fertility in patients with congenital hypogonadotropic hypogonadism. J Clin Endocrinol Metab. 2013; 98:E1790–5.