ABSTRACT
Hypogonadotropic hypogonadism is characterized by failure of gonadal function secondary
to deficient gonadotropin secretion, resulting from either a pituitary or hypothalamic
defect, and is commonly seen in association with structural lesions or functional
defects affecting this region. Although the genetic basis for idiopathic hypogonadotropic
hypogonadism is largely unknown, mutations in several genes involved in the hypothalamo-pituitary-gonadal
axis development and function have recently been implicated in the pathogenesis of
this condition. Genes currently recognized to be involved include KAL-1 (associated with X-linked Kallmann Syndrome), gonadotropin-releasing hormone (GnRH)
receptor, gonadotropins, pituitary transcription factors (HESX1, LHX3, and PROP-1), orphan nuclear receptors (DAX-1, associated with X-linked adrenal hypoplasia congenital, and SF-1), and three genes also associated with obesity (leptin, leptin receptor, and prohormone
convertase 1 [PC1]). Study of these mutations provides an important contribution in the understanding
of the different stages of the reproductive axis development and physiology. Treatment
options currently available for puberty induction, maintenance replacement therapy,
and fertility induction are considered here. Gametogenesis can be induced with either
exogenous gonadotropin or pulsatile GnRH therapy, depending on the etiology.
KEYWORD
Hypogonadotropic hypogonadism - etiology - genetics - treatment