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 HormoneUltimately, 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. At this time, there is no standard protocol for the “ideal” age to begin growth hormone. Since girls with TS are often 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 Practical Guideline titled Care of Girls and Women with Turner Syndrome: A Guideline of the Turner Syndrome Study Group, “ The goals of growth-promoting therapies are to attain a normal height for age as early as possible, progress through puberty at a normal age, and attain a normal adult height.”
Clinical Practice Guidelines http://press.endocrine.org/doi/pdf/10.1210/jc.2006-1374
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
Insurance Coordination: https://www.norditropin.com/how-we-can-help/insurance-coordination
Manufacturer: Eli Lilly
Product: Humatrope http://www.humatrope.com/Pages/index.aspx
Insurance Assistance: http://www.humatrope.com/patient-support-program.html#patient-authorization
Product: Nutropin http://www.nutropin.com/
Patient Support & Financial Services: http://www.nutropin.com/patient-financial-support/insurance-reimbursement-information
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/