GnRH insensitivity is the second most common cause of IHH, responsible for up to 20% of cases.A minority of less than 5-10% is due to inactivating mutations in genes which positively regulate GnRH secretion such as CHD7, KISS1R, and TACR3.The causes of about 25% of all IHH cases are still unknown. Genetics
Treatment
See also
Hypogonadotropic hypogonadism
Hypergonadotropic hypogonadism
Kallmann syndrome
Genetics of GnRH deficiency conditions
HPG axis
Gonads (testicles and ovaries)
GnRH and gonadotropins (FSH and LH)
Sex hormones (androgens and estrogens)
Fertile eunuch syndrome

References


== External links ==
Two types of blood tests are used to confirm the presence of a hormone deficiency: basal levels, where blood samples are taken–usually in the morning–without any form of stimulation, and dynamic tests, where blood tests are taken after the injection of a stimulating substance. Measurement of ACTH and growth hormone usually requires dynamic testing, whereas the other hormones (LH/FSH, prolactin, TSH) can typically be tested with basal levels. There is no adequate direct test for ADH levels, but ADH deficiency can be confirmed indirectly; oxytocin levels are not routinely measured.Generally, the finding of a combination of a low pituitary hormone together with a low hormone from the effector gland is indicative of hypopituitarism. Occasionally, the pituitary hormone may be normal but the effector gland hormone decreased; in this case, the pituitary is not responding appropriately to effector hormone changes, and the combination of findings is still suggestive of hypopituitarism. Basal tests
Levels of LH/FSH may be suppressed by a raised prolactin level, and are therefore not interpretable unless prolactin is low or normal. In men, the combination of low LH and FSH in combination with a low testosterone confirms LH/FSH deficiency; a high testosterone would indicate a  source elsewhere in the body (such as a testosterone-secreting tumor). In women, the diagnosis of LH/FSH deficiency depends on whether the woman has been through the menopause.