Hypogonadotropic hypogonadism is absent or decreased function of the male testes or the female ovaries. It is considered a form of secondary hypogonadism, which means the condition is due to a problem with the pituitary or hypothalamus gland.

See also: Hypogonadism

Gonadotropin deficiency; Secondary hypogonadism; Kallmann syndrome

Hypogonadotropic hypogonadism results from the absence of the gonadal stimulating pituitary hormones: Follicle stimulating hormone (FSH) and Luteinizing hormone (LH).

Normally, the hypothalamus in the brain releases gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release other hormones, including FSH and LH. These hormones tell the female ovaries and male testes to secrete hormones that are responsible for normal sexual development in puberty. A disruption in this chain of events causes a deficiency of the sex hormones and halts normal sexual maturation.

Failure of the hypothalamus is most commonly a result of Kallmann syndrome. Kallmann syndrome is an inherited form of hypogonadotropic hypogonadism that usually includes involves a disorder with the sense of smell.

• Absence of secondary sexual characteristics such as pubic, facial, and underarm hair
• Inability to smell (in some cases)
• Lack of development at puberty (may involve incomplete development or a significant delay in development)
• Underdeveloped testicles
• Short stature (in some cases)

Tests that may be done include:

• Blood tests to measure various hormone levels
• LH response to GnRH
• MRI of the head