Growth hormone deficiency; Dwarfism; Pituitary dwarfism
Growth hormone deficiency involves abnormally short stature with normal body proportions. Growth hormone deficiency can be categorized as either congenital (present at birth) or acquired.
Causes, incidence, and risk factors
An abnormally short height in childhood may occur if the pituitary gland does not produce enough growth hormone . It can be caused by a variety of genetic mutations (such as Pit-1 gene, Prop-1 gene, growth hormone receptor gene, growth hormone gene), absence of the pituitary gland, or severe brain injury, but in most cases no underlying cause of the deficiency is found.
Growth retardation may become evident in infancy and persist throughout childhood. The child’s “growth curve,” which is usually plotted on a standardized growth chart by the pediatrician, may range from flat (no growth) to very shallow (minimal growth). Normal puberty may or may not occur, depending on the degree to which the pituitary can produce adequate hormone levels other than growth hormone.
Growth hormone deficiency may be associated with deficiencies of other hormones, including the following:
- Thyrotropins (control production of thyroid hormones)
- Vasopressin (controls water balance in the body)
- Gonadotropins (control production of male and female sex hormones)
- ACTH or adrenocorticotrophic hormone (controls the adrenal gland and its production of cortisol, DHEA, and other hormones)
Physical defects of the face and skull can also be associated with abnormalities of the pituitary or pituitary function. A small percentage of infants with cleft lip and cleft palate have decreased growth hormone levels.
- Slowed or absent increase in height
- Slow growth before age 5
- Short stature - below 5th percentile on a standardized growth chart, an adult less than 5 feet tall
- Absent or delayed sexual development in an adolescent
- Excessive thirst with excessive urination
- Increased urine volume
Signs and tests
A physical examination including weight, height, and body proportions will show signs of slowed growth rate and deviation from normal growth curves.
Tests include the following:
- A determination of bone age from hand x-ray is often recommended. Bone age can also be determined by DEXA (Dual Energy Xray Absorptiometry).
- Measurement of growth hormone and associated binding protein levels (IGF-I and IGFBP-3) confirms that the disorder is caused by dysfunction of the pituitary gland.
- Other hormone levels should be determined, as lack of growth hormone may not be an isolated problem.
- An x-ray may show skull abnormalities such as small, enlarged, or empty sella or a space-occupying lesion.
- An MRI scan of the head may be ordered to visualize the hypothalamus and pituitary glands.
Synthetic growth hormone can be used for children with growth hormone deficiency. This treatment requires the assistance of a pediatric endocrinologist. Treatment with synthetic (recombinant) human growth hormone is generally considered to be safe, with rare side effects.
If the deficiency is an isolated growth hormone deficiency, synthetic growth hormone is given alone. If the deficiency is not isolated, other hormone replacement preparations will be required as well.
Growth rates are improved in most children treated with growth hormones, although the effectiveness may decrease with prolonged treatment.
If left untreated, extremely short stature and delayed puberty will result from this condition.
In the past, some patients acquired Creutzfeldt-Jacob disease (the human form of “mad cow” disease) from human-derived growth hormone that was used to treat growth deficiencies. This medication has been removed from the market.
Synthetic growth hormone is used instead and carries no risk of infectious disease.
Calling your health care provider
Call your health care provider if your child seems abnormally short for his or her age.
Most cases are not preventable.
by Gevorg A. Poghosian, Ph.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.