Growth Hormone Deficiency in Children
Growth Hormone (GH) deficiency in children is a rare (<1%) condition in which an insufficient amount of growth hormone is produced to promote normal increases in stature. It has been estimated that approximately 22,000 children currently have growth hormone deficiency.
Growth hormone (also known as "somatotropin") is a complicated hormone produced by the pituitary gland - a pea-sized gland located within the brain. Other hormones also produced by the pituitary gland include TSH (thyroid stimulating hormone), FSH (follicle stimulating hormone) and Luteinizing hormone (LH).
A child with growth hormone deficiency may grow normally during the first couple years, but then display a slowing of growth when compared to other children of the same age. Typically this means a growth in height of less than 2 inches per year. Normal growth from ages 2-3 is about 3.5 inches per year. This drops to 2 inches per year from ages 3 to puberty. A doctor will use growth charts and growth curves to assess the growth of a child suspected of having a growth hormone deficiency. Other causes of delayed growth are often explored first, before testing for growth hormone deficiency begins.
CAUSES or Why Did This Happen?
There are other medical conditions which often result in short stature, or a slowed rate of growth in children. These include diseases such as Chronic Renal Insufficiency (CRI), Noonan Syndrome (NS), Prader Willi Syndrome (PWS), Short Stature Homebox-containing Gene Deficiency (SHOX), and Turner Syndrome (TS).
However, true Growth Hormone deficiency is distinguished from these diseases, and there is no known cause. In other words, Growth Hormone Deficiency is not the result of dietary problems or absorption issues. It is not the result of poor nutrition during pregnancy. Growth Hormone Deficiency in Children is not something a parent did wrong. Thankfully, however, there are now a variety of available options for treatment which are generally successful in restoring normal growth patterns.
Historically, from the 1960s to about 1985, the treatment available to treat children for growth hormone deficiency involved the extraction of growth hormone from human cadavers during an autopsy. Yes, you read that right. This extracted growth hormone was then purified and prepared to use, but due to limited supplies it was only available to the most severely effected children.
This approach also posed some significant risks, particularly with respect to the development of CJD (Creutzfeldt-Jacob disease), a neurological disorder that is untreatable and often fatal.
In the early 1980s scientists began to use a relatively new technology (recombinant DNA) to produce a synthetic version of human growth hormone. Success in this research eventually led to the production and FDA approval of the first prescription version of Human Growth Hormone (called "somatropin") by the drug manufacturer Genentech in 1985. The drug was marketed under the name Protropin, although this version of the drug was eventually discontinued and replaced with their newer version in 2004 known as Nutropin.
All growth hormone products are injectable. Parents can be taught to administer the injection to their children at home. The injections are typically given 1-7 times per week, depending on the product.
THE FOLLOWING IS A COMPREHENSIVE LIST OF AVAILABLE TREATMENTS WITH LINKS TO THE RESPECTIVE WEBSITES FOR MORE INFORMATION:
PRESCRIPTION GROWTH HORMONES:
The currently available Growth Hormone products (which all require a prescription in the U.S.) approved to treat Growth Hormone Deficiency in Children (GHDC) are:
GENOTROPIN: This is Pfizer's growth hormone product. The total weekly dose requirement is typically divided up into 6-7 daily doses per week. Their website offers a convenient "Height Comparison Tool" in which you can put in your child's height and age, and compare it to averages.
HUMATROPE: This is Lilly's product for growth hormone replacement. Like Genotropin, it is administered by injection under the skin 6-7 times per week.
NORDITROPIN: Available from Novo Pharmaceuticals, Norditropin is administered 6-7 times weekly by injection. As an added benefit, Novo offers 24/7 access to a trained pharmacist to answer any questions you may have about using your Norditropin product.
NUTROPIN: This is Genentech's product, the original developer of synthetic human growth hormone. Their website provides a great recommended "reading list" for helping parents and children deal with some of the social and emotional issues related to growth hormone deficiencies. Nutropin is given by once-daily injections.
OMNITROPE: Omnitrope is manufactured by Sandoz Biopharmaceuticals in Austria. It is administered 6-7 times per week.
SAIZEN: This is the growth hormone product manufactured by EMD Serono. It may be given on 3 alternate (not consecutive) days per week, 6 days per week, or daily. One unique feature with Saizen is that it can be delivered into the patient with a Needle-Free device, known as the Cool Click!
TEV-TROPIN: Last, but not least, is Teva's growth hormone product known as Tev-Tropin.
Additionally, there are other products which contain growth hormone available, however they are not indicated for the treatment of growth hormone deficiency in children.
DOCTORS AND TESTS
DOCTORS: If you or your pediatrician suspect that your child may have a growth hormone deficiency, he/she will probably recommend an appointment with a specialist. Typically, this will mean a visit to a pediatric endocrinologist. This is a doctor who specializes in treating children for childhood diseases that involve hormones and glands.
A good article explaining the role of a pediatric endocrinologist can be found at: What is a pediatric endocrinologist?
TESTS: In order to determine if your child has a growth hormone deficiency, a specialist will usually conduct a Growth Hormone Stimulation test. This will involve administering one or more substances which are known to stimulate the pituitary gland into secreting growth hormone. The response to this test will help determine if the child is truly growth hormone deficient.
A weight & height chart are standard tools used by physicians to measure the current status of a child's growth deficiency and also to measure improvement after growth hormone therapy has begun.
Below I provide you with links to both a BOYS and GIRLS growth and weight chart for ages 0-3 years (in months). To read these charts, simply find the child's age (in months) along the top or bottom, and then find the child's length (in inches or centimeters) along either side. See where this spot lines up along the curved lines and follow the closest line to the right side of the chart in which you will see their "percent" and "standard deviation" (SD), a more technical way of referring to the growth deficiency. Treatment with growth hormone usually requires a child being in the bottom 3% (or at least 2 standard deviations below average).
The above charts are provided by the CDC (Center for Disease Control).
REFERENCES & RESOURCES
- The Magic Foundation- Very good brief article on Growth Hormone Deficiency
- Medscape - Well written article with a bit more technical information
- New York Times Health Guide - Not highly technical, but accurate and easy to read
- PubMed- A brief medical encyclopedia article on Growth Hormone Deficiency in Children
- Understanding Growth Hormone Therapy - EXCELLENT! A well-written 16 page straightforward discussion about growth hormone deficiency and treatment.
- The Growth Hormone Foundation - A TON of resources from the leading organization on growth hormone disorders