Growth hormone deficiency is a condition that typically causes abnormally short height in children, although the symptoms vary depending on age. The hormone, also called somatotropinin, is produced by the pituitary gland, located at the base of the brain.
The cause of the deficiency could be due to a number of reasons. It may exist at birth or develop after a head injury or medical condition that cause abnormal levels of hormones related to the endocrine glands. Cells in the pituitary gland that produce growth hormone are very sensitive to radiation and trauma. The condition can develop after radiation treatment for brain cancer or hormonal problems involving the pituitary gland or hypothalamus. Often, no cause is identified.
Growth hormone deficiency is most often diagnosed in children, rather than adults. Children with the condition have a slow rate of growth, usually less than 2 inches a year. In older children, the condition can result in delayed puberty or the absence of puberty.
In adults, symptoms include a decrease in energy and lean muscle mass, increase in fat, and a feeling of social isolation. Patients may have difficulty exercising. Another common symptom is osteoporosis.
To diagnose the condition, a physical exam and medical history will be performed to identify symptoms. In a child, weight, height and body proportions are measured to determine if there's a slow rate of growth.
In addition, the following tests may be performed:
Synthetic growth hormone, administered as daily injections, has proven to be an effective treatment of growth hormone deficiency.
In children, growth hormone replacement is critical for growth and development.
In adults, replacement therapy was controversial in the past but is now widely accepted.
Successful treatment with hormone replacement may be dependent on the patient's level of insulin-like growth factor 1 (IGF-1), which plays an important role in childhood growth. Its production is stimulated by growth hormone.
For patients with low levels of IGF-1, growth hormone levels can be adjusted to bring IGF-1 levels within a normal range. Benefits usually are noted in six to 18 months.
For patients with normal levels of IGF-1, there may be no benefit from growth hormone therapy.
Reviewed by health care specialists at UCSF Medical Center.