A growth hormone deficiency (GHD) occurs when the pituitary gland doesn’t produce enough growth hormone. It affects children more often than adults.
The pituitary gland is a small gland about the size of a pea. It’s located at the base of the skull and secretes eight hormones. Some of these hormones control thyroid activity and body temperature.
GHD occurs in roughly 1 out of 7,000 births. The condition is also a symptom of several genetic diseases, including Prader-Willi syndrome.
You may be concerned that your child isn’t meeting height and weight growth standards. But if it’s GHD, it’s important to know that it’s treatable. Children who are diagnosed early often recover very well. If left untreated, the condition can result in shorter-than-average height and delayed puberty.
Your body still needs growth hormone after you’ve finished puberty. Once you’re in adulthood, the growth hormone maintains your body structure and metabolism. Adults can also develop GHD, but it isn’t as common.
GHD that isn’t present at birth may be caused by a tumor in the brain. These tumors are normally located at the site of the pituitary gland or the nearby hypothalamus region of the brain.
In children and adults, serious head injuries, infections, and radiation treatments can also cause GHD. This is called acquired growth hormone deficiency (AGHD).
Most cases of GHD are idiopathic, meaning that no cause has yet been found.
Children with GHD are shorter than their peers and have younger-looking, rounder faces. They may also have “baby fat” around the abdomen, even though their body proportions are average.
If GHD develops later in a child’s life, such as from a brain injury or tumor, its main symptom is delayed puberty. In some instances, sexual development is halted.
Many teens with GHD experience low self-esteem due to developmental delays, such as short stature or a slow rate of maturing. For example, young women may not develop breasts and young men’s voices may not change at the same rate as their peers.
Reduced bone strength is another symptom of AGHD. This may lead to more frequent fractures, especially in older adults.
People with low growth hormone levels may feel tired and lack stamina. They may experience sensitivity to hot or cold temperatures.
Those with GHD may experience certain psychological effects, including:
Adults with AGHD typically have high levels of fat in the blood and high cholesterol. This isn’t due to poor diet, but rather to changes in the body’s metabolism caused by low levels of growth hormone. Adults with AGHD are at greater risk for diabetes and heart disease.
Your child’s doctor will look for signs of GHD if your child isn’t meeting their height and weight milestones. They’ll ask you about your growth rate as you approached puberty, as well as your other children’s growth rates. If they suspect GHD, a number of tests can confirm the diagnosis.
Your levels of growth hormone fluctuate widely throughout the day and night (diurnal variation). A blood test with a lower-than-normal result isn’t enough evidence in itself to make a diagnosis.
One blood test can measure levels of proteins which are markers of growth hormone function but are much more stable. These are IGF-1 (insulin-like growth factor 1) and IGFPB-3 (insulin-like growth factor binding protein 3).
Your doctor may then go on to a GH stimulation test, if screening tests suggest that you have a GH deficiency.
Growth plates are the developing tissue at each end of your arm and leg bones. Growth plates fuse together when you’ve finished developing. X-rays of your child’s hand can indicate their level of bone growth.
If a child’s bone age is younger than their chronological age, this might be due to GHD.
If your doctor suspects a tumor or other damage to the pituitary gland, an MRI imaging scan can provide a detailed look inside the brain. Growth hormone levels will often be screened in adults who have a history of pituitary disorders, a brain injury, or who need brain surgery.
Testing can determine whether the pituitary condition was present at birth or brought on by an injury or tumor.
Since the mid-1980s, synthetic growth hormones have been used with great success to treat children and adults. Before synthetic growth hormones, natural growth hormones from cadavers were used for treatment.
Growth hormone is given by injection, typically into the body’s fatty tissues, such as the back of the arms, thighs, or buttocks. It’s most effective as a daily treatment.
Side effects are generally minor, but may include:
In rare cases, long-term growth hormone injections may contribute to the development of diabetes, especially in people with a family history of that disease.
Long-term treatment
Children with congenital GHD are often treated with growth hormone until they reach puberty. Often, children who have too little growth hormone in their youth will naturally begin to produce enough as they enter adulthood.
However, some remain in treatment for their entire lives. Your doctor can determine whether you need ongoing injections by monitoring hormone levels in your blood.
Make an appointment with your doctor if you suspect that you or your child is deficient in growth hormones.
Many people respond very well to treatment. The sooner you start treatment, the better your results will be.
Congenital GHD results from genetic error, and may be associated with brain structure defects or with midline facial defects such as a cleft palate or single central incisor.
Several genetic defects have been identified:
Growth hormone deficiency IA is autosomal recessive and is characterized by growth retardation in utero. Affected children are small in relation to their siblings. The infant usually has a normal response to administration of human growth hormone (hGH) at first, but then develops antibodies to the hormone and grows into a very short adult.
Growth Hormone Deficiency IB is also autosomal recessive and is similar to IA. However, there is some growth hormone (GH) present in the child at birth and usually the child continues to respond to hGH treatments.
Growth Hormone Deficiency IIB and III are similar to IB, but IIB is autosomal dominant and III is X-linked.
Classic genetic diseases are the product of the interaction of two genes, one received from the father and one from the mother.
Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary to cause a particular disease. The abnormal gene can be inherited from either parent or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy. The risk is the same for males and females.
Recessive genetic disorders occur when an individual inherits two copies of an abnormal gene for the same trait, one from each parent. If an individual receives one normal gene and one gene for the disease, the person will be a carrier for the disease but usually will not show symptoms. The risk for two carrier parents to both pass the defective gene and have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier like the parents is 50% with each pregnancy.
The chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%. The risk is the same for males and females.
Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk of having children with a recessive genetic disorder.
X-linked genetic disorders are conditions caused by an abnormal gene on the X chromosome and manifest mostly in males. Females that have a defective gene present on one of their X chromosomes are carriers for that disorder. Carrier females usually do not display symptoms because females have two X chromosomes and only one carries the defective gene. Males have one X chromosome that is inherited from their mother and if a male inherits an X chromosome that contains a defective gene he will develop the disease.
Female carriers of an X-linked disorder have a 25% chance with each pregnancy to have a carrier daughter like themselves, a 25% chance to have a non-carrier daughter, a 25% chance to have a son affected with the disease and a 25% chance to have an unaffected son.
If a male with X-linked disorders is able to reproduce, he will pass the defective gene to all of his daughters who will be carriers. A male cannot pass an X-linked gene to his sons because males always pass their Y chromosome instead of their X chromosome to male offspring.
Acquired GHD can occur as a result of many different causes including brain trauma (perinatal or postnatal), central nervous system infection, tumors of the hypothalamus or pituitary (pituitary adenoma, craniopharyngioma, Rathke’s cleft cyst, glioma, germinoma, metastases), radiation therapy, infiltrative diseases (Langerhans cell histiocytosis, sarcoidosis, tuberculosis), or, if without another diagnosis, it is considered idiopathic.
Somatotropin; GH; human growth hormone; HGH
What is growth hormone?
Growth hormone is released into the bloodstream from the anterior pituitary gland. The pituitary gland also produces other hormones that have different functions from growth hormone.
Growth hormone acts on many parts of the body to promote growth in children. Once the growth plates in the bones (epiphyses) have fused growth hormone does not increase height. In adults, it does not cause growth but it helps to maintain normal body structure and metabolism, including helping to keep blood glucose levels within set levels.
How is growth hormone controlled?
Growth hormone release is not continuous; it is released in a number of ‘bursts’ or pulses every three to five hours. This release is controlled by two other hormones that are released from the hypothalamus (a part of the brain): growth hormone-releasing hormone, which stimulates the pituitary to release growth hormone, and somatostatin, which inhibits that release.
Growth hormone levels are increased by sleep, stress, exercise and low glucose levels in the blood. They also increase around the time of puberty. Growth hormone release is lowered in pregnancy and if the brain senses high levels of growth hormone or insulin-like growth factors already in the blood.
What happens if I have too much growth hormone?
Not surprisingly, too much growth hormone causes too much growth. In adults, excessive growth hormone for a long period of time produces a condition known as acromegaly, in which patients have swelling of the hands and feet and altered facial features. These patients also have organ enlargement and serious functional disorders such as high blood pressure, diabetes and heart disease. Over 99% of cases are due to benign tumours of the pituitary gland, which produce growth hormone. This condition is more common after middle-age when growth is complete so affected individuals do not get any taller.
Very rarely, increased growth hormone levels can occur in children before they reach their final height, which can lead to excessive growth of long bones, resulting in the child being abnormally tall. This is commonly known as gigantism (a very large increase in height).
Overproduction of growth hormone is diagnosed by giving a sugary drink and measuring the growth hormone level over the next few hours. The sugar should cause growth hormone production to reduce. However, this does not happen in acromegaly.
What happens if I have too little growth hormone?
Too little growth hormone (deficiency) results in poor growth in children. In adults, it causes a reduced sense of wellbeing, increased fat, increased risk of heart disease and weak heart, muscles and bones. The condition may be present from birth where the cause can be unknown, genetic or due to injury to the pituitary gland (during development or at birth).
Growth hormone deficiency may also develop in adults due to brain injury, a pituitary tumour or damage to the pituitary gland (for example, after brain surgery or radiotherapy for cancer treatment). The main treatment is to replace the growth hormone using injections - either once a day or several times a week.
In the past, growth hormone treatment was stopped at the end of growth. It is now clear that growth hormone contributes to both bone mass and muscle mass reaching the best possible level, as well as reducing fat mass during development to an adult. The specialist is therefore likely to discuss the benefits of continuing growth hormone after growth has completed until age 25 to make sure bone and muscle mass reach the best possible level. Additionally, growth hormone has been linked to a sensation of wellbeing, specifically energy levels. There is evidence that 30-50% of adults with growth hormone deficiency feel tired to a level that impairs their wellbeing. These adults may benefit from lifelong treatment with growth hormone. Taking growth hormone when adult will not result in increased height.
Last reviewed: May 2021