Genetics of hypogonadotropic hypogonadism.
Determining the physiologic influences that modulate GnRH secretion, the prime initiator of reproductive function in the human, is fundamental not only to our understanding of the rare condition of congenital idiopathic hypogonadotropic hypogonadism (IHH), but also common disorders such as constitutional delay of puberty and hypothalamic amenorrhea. IHH is characterized by low levels of sex steroids and gonadotropins, normal findings on radiographic imaging of the hypothalamic-pituitary regions, and normal baseline and reserve testing of the remainder of the hypothalamic-pituitary axes. Failure of the normal pattern of episodic GnRH secretion results in delay of puberty and infertility. IHH is characterized by rich clinical and genetic heterogeneity, variable modes of inheritance, and association with other anomalies. To date, 4 genes have been identified as causes of IHH in the human; KAL [the gene for X-linked Kallmann syndrome (IHH and anosmia)], DAX1 [the gene for X-linked adrenal hypoplasia congenita (IHH and adrenal insufficiency)], GNRHR (the GnRH receptor), and PC1 (the gene for prohormone convertase 1, causing a syndrome of IHH and defects in prohormone processing). As these mutations account for less than 20% of all IHH cases, discovery of additional gene mutations will continue to advance our understanding of this intriguing syndrome.
Seminara
S B
SB
Reproductive Endocrine Unit, Massachusetts General Hospital, Boston 02114, USA. seminara.stephanie@mgh.harvard.edu
Oliveira
L M
LM
Beranova
M
M
Hayes
F J
FJ
Crowley
W F
WF
D016282:Aspartic Acid Endopeptidases / Q000235:genetics; D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins / Q000235:genetics; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D006065:Gonadotropins, Pituitary / Q000172:deficiency*; D006801:Humans; D007006:Hypogonadism / Q000235:genetics*; D017436:Kallmann Syndrome / Q000235:genetics; D009154:Mutation; D043484:Proprotein Convertases; D011966:Receptors, LHRH / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000235:genetics; D012097:Repressor Proteins; D014157:Transcription Factors / Q000235:genetics
D057137:DAX-1 Orphan Nuclear Receptor; D004268:DNA-Binding Proteins; D006065:Gonadotropins, Pituitary; C539965:NR0B1 protein, human; D011966:Receptors, LHRH; D018168:Receptors, Retinoic Acid; D012097:Repressor Proteins; D014157:Transcription Factors; D007987:Gonadotropin-Releasing Hormone; D043484:Proprotein Convertases; D016282:Aspartic Acid Endopeptidases