GROWTH HORMONE – Yes or No?
In 1996, the US Food and Drug Administration approved human growth hormone (hGH) as standard treatment for Turner syndrome (TS). Today, it is considered a safe and effective treatment to promote growth in girls who have been diagnosed with TS. The average height of an adult woman with TS who is not treated with growth hormone is 4 ft. 8 in. By starting treatment early, and maintaining it throughout a child’s growing years, girls with TS can reach a more typical final height.
Although rare, growth hormone can result in serious side effects, and families should consult a medical professional to educate themselves about the benefits and risks of growth hormone. Girls on growth hormone typically visit an endocrinologist every few months to monitor growth and check for adverse side effects.
When to Start Growth Hormone
Per the Clinical Practice Guidelines, “the optimal age for initiation of GH treatment has not been firmly established, but various lines of evidence indicate that younger age at treatment initiation, including at least 4 years of treatment prior to puberty, is associated with greater treatment effect. Analyses of large cohort studies followed in national or pharmaceutical company-sponsored registries report a similar positive effect of younger age at treatment initiation.”
“Relatively early GH initiation, around 4–6 years of age, is likely to result in greater height gains during childhood and allow for age-appropriate induction of feminization, such that the goals for both optimal adult stature and timing of puberty can be achieved. Therapy may be continued until the girl is satisfied with her height or until little growth potential remains. There is no physiological rationale for continuing GH treatment into the transition period after the completion of puberty.”
Ultimately, the decision to begin growth hormone treatments should be made in consultation with a doctor who is knowledgeable about both Turner syndrome and growth hormone. For girls with TS who are not diagnosed as infants, the timing of treatment is often driven by lack of growth compared to peers at the time of diagnosis.
What is Growth Hormone?The generic name for growth hormone is somatotropin, although growth hormone is also referred to as GH, human growth hormone, HGH, and hGH.
In the human body, growth hormone is one of the hormones produced in the pituitary gland and released into the bloodstream to regulate different systems. Growth hormone regulates growth in a child.
From the 1960’s to the early 1980’s, growth hormone was procured from the brains of human cadavers. The growth hormone prescribed today is recombinant human growth hormone, or rHGH, and is artificially produced in a lab. Recombinant HGH is a protein of amino acids that are encoded by a DNA sequence.
How Does Growth Hormone Work?In the past, it was believed that short stature in TS was caused by reduced growth hormone (GH) secretions. However, research studies in the 1980’s disproved this and discovered that individuals with TS have an abnormal growth hormone-insulin-like growth factor or IGF binding protein. In 1997, the SHOX gene was identified as contributing to the short stature demonstrated in TS. The SHOX gene is located on the ends of the X chromosomes and act to repress growth plate fusion. If the second X chromosome is missing or altered, the absence of the second SHOX gene could contribute to short stature. Maximum growth seems to occur when recombinant human growth hormone is combined with estrogen replacement therapy.
According to the Clinical Practice Guidelines, “the goals of growth-promoting therapies are to facilitate attainment of heights during childhood and adulthood that minimize physical restrictions and allow puberty to begin at an age similar to peers.”
SHOXThe SHOX gene is defined by The Free Dictionary as the following: Short stature homeobox gene or SHOX is a gene on the X chromosome and Y chromosome which is associated with short stature in humans if mutated or present in only one copy (haploinsufficiency). The gene was first found during a search for the cause of short stature in women with Turner syndrome, in which there is loss of genetic material from the X chromosome, sometimes by loss of one entire X chromosome. The SHOX gene is contained on the distal ends of the short arms of the X and Y chromosomes (pseudoautosomal part of the gene). The SHOX gene encodes a protein, which is a transcription factor. A transcription factor is a type of protein that enhances the expression of other genes involved in various developmental processes. This transcription factor contains a homeo domain, a special protein sequence that is able to bind to DNA and is involved in the regulation of multiple genes. Two active copies of the SHOX gene are needed for full expression of the protein. Deficiency of one copy of SHOX is associated with short stature in some patients. The SHOX gene is essential for the development of the skeleton. It plays a particularly important role in the growth and maturation of bones in the arms and legs.
Because the SHOX gene is located on the sex chromosomes, most women with Turner syndrome have only one copy of the gene in each cell instead of the usual two copies. Loss of one copy of this gene reduces the amount of SHOX protein that is produced. A shortage of this protein likely contributes to the short stature and skeletal abnormalities (such as unusual rotation of the wrist and elbow joints) often seen in females with Turner Syndrome.
Growth Hormone Providers
Growth hormone is delivered via injections, often 6-7 times a week. Common brands of growth hormone include Norditropin, Genotropin, Humatrope, and Nutropin. The generic version of human growth hormone is called somatropin. Your doctor will monitor your growth closely to determine the best dose and delivery system.
The growth hormone brand you are prescribed will depend on what your insurance covers and your doctor’s preferences. Some patients have found that they prefer the injection delivery device of one manufacturer over another.
Here is a list of the pharmaceutical companies that manufacturer growth hormone for treatment of TS in the USA. Each company has detailed drug information, including benefits and potential side effects, as well as patient assistance contacts.
Manufacturer: Novo Nordisk
Product: Norditropin https://www.norditropin.com/
Patient Services: https://www.norditropin.com/how-we-can-help/patient-services.html
Insurance Coordination: https://www.norditropin.com/how-we-can-help/navigating-insurance-obstacles.html
Manufacturer: Eli Lilly
Product: Humatrope https://www.humatrope.com/what-is-humatrope
Patient Support: https://www.humatrope.com/support
Insurance Assistance: https://www.humatrope.com/support/insurance-assistance
Product: Nutropin http://www.nutropin.com/
Manufacturer: EMD Serono
Product: Saizen http://www.saizenus.com/
Patient Support: http://www.saizenus.com/getting-help/patient-support-services/
Product: Genotropin http://www.genotropin.com/
Patient Support: http://www.genotropin.com/pfizer-bridge-program
Product: Omnitrope http://www.omnitrope.com/
Patient Support: http://www.omnitrope.com/patient-support/index.shtml
Manufacturer: Teva Pharmaceuticals
Product: Tev-Tropin http://www.tevausa.com/
For additional links, visit the Human Growth Foundation at http://www.hgfound.org/res_rGHmanufacturers.asp
For additional information about growth in general as well as help with insurance issues, visit The Magic Foundation: https://www.magicfoundation.org/