China
Africa
Explore chapters and articles related to this topic
Andrology
Published in Manit Arya, Taimur T. Shah, Jas S. Kalsi, Herman S. Fernando, Iqbal S. Shergill, Asif Muneer, Hashim U. Ahmed, MCQs for the FRCS(Urol) and Postgraduate Urology Examinations, 2020
Klinefelter’s syndrome (47,XXY) is the most frequent sex chromosome abnormality. Testosterone levels are normal or low. Androgen replacement may be needed in these men as they age. Germ cell presence and sperm production are variable in patients with mosaicism (46,XY/47,XXY). All patients of Klinefelter’s syndrome who have undergone sperm retrieval should have a long-term endocrinological review. Kallman syndrome is the most common X-linked disorder in infertility. It is X-linked recessive disorder (mutation in KALIG1 gene on Xp22.3). these patients have hypogonadotropic hypogonadism with anosmia and infertility. Spermatogenesis can be induced by hormonal treatment. Reifenstein syndrome is a state of partial androgen insensitivity with predominantly male phenotype including micropenis, perineal hypospadias and cryptorchidism. Complete androgen insensitivity syndrome (Morris syndrome), the phenotype is of female external genitalia and absence of pubic hair.
Physiology of the Pituitary Gland
Published in John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie, Basic Sciences Endocrine Surgery Rhinology, 2018
Mária Hérincs, Karen Young, Márta Korbonits
There is an interesting interface between the gonadal axis and the olfactory system. During embryogenesis, GnRH cells are located at the top of the nasal cavity together with cells of the olfactory system. GnRH cells then migrate to the hypothalamus. Patients with loss-of-function mutations in peptides involved in this migration develop hypothalamic hypogonadism. When this condition occurs in combination with decreased sense of smell, either partial (hyposmia) or total (anosmia), the underlying condition is referred to as Kallmann syndrome.32 From an ENT perspective, the condition is associated with craniofacial defects such as cleft palate and sensorineural hearing loss.
Severe male factor infertility: Genetic consequences and recommendations for genetic testing
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
Katrien Stouffs, Willy Lissens, Sara Seneca
Kallmann syndrome is characterized by hypogonado- tropic hypogonadism, due to impaired gonadotropin- releasing hormone secretion, and anosmia. X-linked as well as autosomal recessive and autosomal dominant inheritance forms exist. The X-linked form of Kallmann syndrome (KALI gene) is the most frequent and the best known one (47). An autosomal dominant form of Kallmann syndrome is caused by mutations in the FGFR1 gene (48). A possible interaction between the gene products of the KALI and FGFR1 genes has been suggested as an explanation for the higher prevalence of Kallmann syndrome in males than in females (49, 50). In addition, mutations in four other genes have been implicated in Kallmann syndrome (51–53). Nevertheless, only about 30% of patients with a clinical diagnosis of Kallmann syndrome have mutations in one of the six genes identified so far (54). The presence of mutations in different genes of some individuals suggests that, at least in some patients, a possible digenic mode of inheritance of Kallmann syndrome exists (51, 55, 56). Hormonal treatment will stimulate spermatogenesis in patients with Kallmann syndrome (57). Genetic counseling is indicated.
The evaluation of ovarian function in normosmic idiopathic hypogonadotropic hypogonadism with a fibroblast growth factor receptor 1 mutation: a case report
Published in Gynecological Endocrinology, 2022
Idiopathic hypogonadotropic hypogonadism (IHH) is a relatively uncommon disorder with prevalence ranging from 1 in 10,000 to 1 in 100,000. The incidence rate of male is higher than that of female, and the ratio of male to female is 5:1 [1]. IHH is diagnosed in the presence of low pituitary gonadotropic hormone such as the production of follicle-stimulating hormone (FSH), luteinizing hormone (LH) without any structural or functional abnormalities in the hypothalamic-pituitary-gonadal axis [2]. Gonadotropin-releasing hormone (GnRH) plays a pivotal role in the initiation of the reproductive hormone cascade. Formed in hypothalamic neurons, GnRH is released in a pulsatile manner into the hypophyseal portal circulation to stimulate the biosynthesis and secretion of the pituitary gonadotropins, LH and FSH [3]. IHH is primarily due to a flaw in the synthesis, secretion and action of GnRH or GnRH neuron migration anomalies. According to whether the patients are combined with olfactory disorders, the disease is divided into two categories. Those with olfactory disorders are called Kallman syndrome. The incidence rate is about 1/10000, accounting for 1/10 of IHH. Normal olfaction is called normosmic IHH (nIHH) [2,4].
Contemporary genetics-based diagnostics of male infertility
Published in Expert Review of Molecular Diagnostics, 2019
Alberto Ferlin, Savina Dipresa, Andrea Delbarba, Filippo Maffezzoni, Teresa Porcelli, Carlo Cappelli, Carlo Foresta
Kallmann syndrome has a frequency of 1:10.000 and is characterized by hypogonadotropic hypogonadism (HH) (low serum level of testosterone, LH and FSH) and anosmia or hyposmia [68,69]. Beyond HH and midline defects such as cleft palate, other clinical features associated with Kallmann syndrome include tall stature, cryptorchidism, unilateral renal agenesis, and neurogenic deafness [68,69]. The most frequent genetic alteration responsible for this syndrome is a mutation in the X-linked gene KAL1 (14% of familial cases and 11% of sporadic cases), encoding the protein anosmin-1, which is a cell adhesion protein of the extracellular matrix. During embryogenesis, anosmin-1 is required for the organized migration of both olfactory axons and GnRH neurons from the olfactory placode through the cribriform plate and into the preoptic area of the hypothalamus. As such, defects result in anosmia and GnRH deficiency. GnRH deficiency results in subsequent lack of pulsatile LH that is required for normal gonadal function. Recent advance in this field, however, identified many other genes involved in HH mapping on chromosomes other than X chromosome (see below).
Identification of a novel mutation in FGFR1 gene in patients with Kallmann syndrome by high throughput sequencing
Published in Systems Biology in Reproductive Medicine, 2018
Bao-Fang Jin, Zhi-Yong Ji, Zhi-Ying Su, Li-Bin Mei, Xian-Jing Huang, Shao-Bin Lin, Ping Li, Yan-Wei Sha
Kallmann syndrome (KS) is a hereditary disease that originates from gonadotropin releasing hormone deficiency and olfactory loss, but it is often accompanied by various non-reproductive phenotypes, such as bone, eye, ear, kidney and heart defects. The nerve cell of GnRH and osmatic fiber that migrates in an aberrant way during embryonic development may lead to the absence of olfactory sense (Raivio et al. 2007; Mitchell et al. 2011; Sidhoum et al. 2014).