One area of the brain, the hypothalmus, secretes hormones (GnRH) to stimulate the pituitary gland. In response, the pituitary gland (located near the brain) secretes other hormones (FSH and LH).

These, in turn, stimulate the ovaries (female) and testes (male) to secrete hormones that are responsible for normal sexual development in puberty. Any disruption in this cascade causes a deficiency of the sex hormones and halts normal pubertal sexual maturation.

Failure of the hypothalamus is most commonly a result of Kallmann syndrome. Kallmann syndrome is an inherited disorder that usually includes a disorder of the sense of smell. Failure of the pituitary may result from empty sella syndrome, pituitary tumors (craniopharyngioma), head injuries, or other causes.

• lack of development at puberty, incomplete development or significant delay of pubertal development
• prepubertal testicular size in adolescence
• absence of secondary sexual development (e.g., pubic, facial, axillary hair)
• short stature may be associated with some forms of hypogonadism
• anosmia (inability to smell)

• levels of various hormones in the blood
• GnRH stimulation test (measuring hormone levels after stimulation by injected hormones)
• MRI of the head

Treatment depends on the source of the defect.

• intramuscular (IM) testosterone
• estrogen and progesterone pills
• GnRH injections

With proper hormonal stimulation, puberty can be induced and fertility may be restored.

• delayed puberty
• infertility
• low self-esteem (Children who do not develop puberty changes until late may suffer from comparison with their peers. Lots of emotional support may be helpful.)

Call your health care provider if your child does not enter puberty as expected.

Prevention is dependent on the cause. Genetic counseling may be appropriate for individuals with heritable disorders that are associated with hypogonadism. Prevention of serious head injuries reduces the risk of pituitary injury associated hypogonadotropic hypogonadism.