Growth hormone (GH) plays a central role in the growth process and maturation from child to adulthood. It also regulates a number of metabolic and physiological processes throughout life. GH deficiency occurs when the pituitary gland in the brain is unable to produce or release sufficient amounts of GH.
Growth Hormone Deficiency (GHD) can be grouped into 3 types:
- Congenital: caused by a problem with the pituitary gland or hypothalamus during fetal development
- Acquired: caused by damage to the pituitary gland or hypothalamus from tumors, severe head injury or infections such as meningitis or encephalitis
- Idiopathic: unknown cause
In normal children, GH works throughout the body to stimulate growth. Not having enough of this hormone affects the body’s basic supplies for growth. This lack has a number of consequences:
- inability to make enough new proteins to build muscles, resulting in weakness and impact on the ability to exercise
- failure to stimulate production of other hormones, such as insulin-like growth factor (IGF-1), which is especially important in stimulating bone growth
- failure to signal other parts of the body involved in growth
In children, lack of GH results in short stature, delayed maturation and inability to grow strong bones. In addition, the face may remain childish and the child may accumulate increased fat particularly around the stomach area.
The earlier a treatable growth problem is detected, the better the child’s chance of achieving a normal height throughout childhood and realizing his or her full growth potential. In a society that places great emphasis on height, children who are short for their age sometimes have problems because playmates and teachers treat them as though they are younger rather than just smaller.
Other related growth disorders include:
- Small for Gestational Age (SGA)
Babies born small for gestational age (SGA) as compared with other babies who had the same amount of time in the womb generally grow extra fast in the first months of life; thanks to this ‘catch up’ growth, they often reach the same size as normal babies by about 2 years of age. If this is not the case, extra GH can help SGA babies achieve normal adult height. - Turner Syndrome (TS)
Named after the endocrinologist Dr Henry Turner who first described the condition in 1938, Turner Syndrome is caused by a genetic defect that occurs only in girls. Most girls are born with two female X chromosomes; in girls born with TS one of the two X chromosomes is missing, incomplete or damaged. TS can cause growth disorders and short stature. Early GH therapy has been shown to increase the rate of gain in height in girls with TS and may increase final adult height. - Chronic renal failure (CRF)
Also known as chronic kidney disease, CRF describes kidney malfunction that develops gradually over time (at least three months). As CRF progresses, the kidneys become less able to remove wastes and extra water from the body. Children with CRF often have poor growth and can be treated by GH.
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