Growth and Growth Hormone Therapy
Growth and Height Management
Short stature is one of the most common and easily recognizable features of TS, with an average adult height being 4’8”, without growth hormone (GH) treatment. Most girls with TS produce GH, but their bodies don’t respond to it effectively. Growth failure in TS often begins before birth and continues during infancy and childhood. About 75% of girls with TS fall don't reach the 5th percentile in height, on the standard female growth chart, by 3.5 years of age. Girls with a mosaic form of TS vary more in their growth, yet 50% are shorter than 95% of other 2-year-old girls.
A Turner syndrome growth chart is available for those below the 0% percentile on the standard growth chart; a chart for age 2 years and younger does not exist for TS.
Most girls with TS not treated with growth or sex hormones including those who have spontaneous puberty, will not have a pubertal growth spurt yet may grow at a slow rate until they are in their late teens. Puberty speeds up bone growth and maturation, so it is recommended that puberty in TS be initiated with estrogen replacement therapy around 11-12 years of age. Physical growth stops when the growth plates of the bones fuse together, happening at a bone age of about 15 years. Many girls with TS have a delayed bone age, meaning that their bones grow slower than typical for their age so a 13-year-old girl with TS may have a bone age of 11 years, so she has the potential to grow for a longer period of time. It is recommended to begin GH therapy around 4–6 years of age, or earlier if growth failure is already noticeable. Continue therapy until satisfied with final height or until little growth potential remains.
What happens if I don’t want to or am unable to treat my daughter with GH?
It's okay, GH therapy is optional and a personal decision. studies on TS and height suggest that height is not a predictor of life satisfaction. Women with TS who have not had GH therapy have various adult heights, from 4’6-5’3”, as mentioned mosaic TS is related to heights over 5’ without GH therapy. Women of all heights often mention the same challenges and accomplishments.
What is growth hormone?
Natural human growth hormone (HGH) is produced by a part of the brain called the pituitary gland. It is important for muscle and bone growth, regulates body composition, body fluids, sugar and fat metabolism, and possibly heart function. GH stimulates the liver to produce IGF-I (insulin-like growth factor I) important for bone growth. A biosynthetic form of HGH (made in a lab) is available for medical use and is FDA approved for treatment in TS. The goals of growth-promoting therapies are to attain a typical height for age as early as possible, progress through puberty at a normal age, and attain a typical adult height.
How does the GH therapy process work?
A pediatric endocrinologist will prescribe the GH medication and contact the insurance company for approval. If your insurance is not cooperative, directly contact the GH company your insurance company requires you to use. After the insurance company approves GH therapy, medication will arrive in the mail, sent by a specialty pharmacy.
Although there are many GH companies, the medications are similar, the injection device is the main difference. The saline and other minor differences may rarely impact side effects so report any stinging or other issues to the endocrinologist.
GH is injected, as a shot, into the fatty tissue of either the thigh, stomach, hip or back of arm every day. The shot comes in various devices that use short needles and a nurse will teach you all about the process. You’ll be a pro at giving the shots in no time and your daughter should adapt quickly too. If you need additional support you can speak to the health navigator and talk to other parents too.
Some girls prefer shots to be given when they are asleep (ask permission first)
Celebrating growth with new shoes, clothes and charts at home make the shots a little more bearable.
Allowing your daughter to watch videos of other girls getting their shots may be helpful.
The initial dose is recommended at 0.03 mg/kg/day (for the U.S.)
It is not recommended to add very-low-dose of estrogen replacement before puberty age to promote growth.
Is Growth Hormone Therapy Safe?
Long-term medical studies are reassuring with respect to blood pressure (BP) and risk factors for heart-related disease, blood sugar and fat metabolism, body composition, bone mineralization, body proportions, and occurrence of ear infections and hearing loss.
Studies indicate that girls with TS taking growth hormone appear to be at increased risk of:
•Intracranial hypertension (pressure built-up in the head) rare occurrences
•Slipped capital femoral epiphysis (hip pain and limp); rare occurrences
•Development or progression of scoliosis (abnormal curvature of the back)
•Possible greater risk of pancreatitis; very low risk
How Much Does Growth Hormone Therapy Cost?
Costs vary because the dose is based on weight, how the body utilizes the hormone and insurance coverages. The TSSUS office or your doctor can help you understand options available to you and many pharmaceutical companies offer patient assistance programs to help obtain approval for coverage or financial assistance. It’s confusing to list any real dollar amounts but some estimates suggest $52,634 per inch (per 2.54 cm), this is the cost of the medication only, without factoring in insurance.
What Results Should We Expect?
Girls with TS may expect an average final height gain of 2.8 inches. However, results can range from no gain to over 4.7 inches, dependent on the age when GH is started, dosage, how consistent the shot is given (every day) when estrogen therapy is started, and how the body responds to growth hormone.
GH treatment is associated with height gains of 2 to 3.5 inches over treatment periods ranging from 5.5 to 7.5 years in several medical studies. A height gain of about 1 cm per year is a reasonable expectation. Some studies have shown height gains exceeding this, with height improvement sometimes reaching up to 4 to 5 inches when compared to the predicted adult height at the beginning of GH treatment.
GH may be combined with another medication called Oxandrolone if adult height outcome is likely to be unsatisfactory with GH alone. Studies have shown slight increases in growth response (1 to 2 inches). There is a chance of unwanted effects such as delayed breast development, clitoris enlargement, voice-deepening, male-pattern hair growth, and acne. When correctly dosed, these complications can be avoided. Oxandrolone should not be prescribed before 9–10 years of age.
Growth Hormone & Estrogen Replacement Therapies in Turner Syndrome
Helpful Resources for Growth in TS
The Turner Syndrome: A Guide for Families discusses growth in depth such as bone age, mosaicism and growth, growth charts, how to use a growth chart, quality of life and short stature, and best outcomes of for increased adult height in TS.
Turner Syndrome growth chart; for 2 through 19 years old.
Companies that produce growth hormone in the United States may offer Patient Assistance Programs for obtaining GH through insurance companies, payment assistance, and other helpful information.
GH companies and medications in the U.S.:
Somatropin is the generic version of GH
The TSSUS health navigator at 1-800-265-9944 or can assist in determining personal decisions regarding growth in TS and connect you to volunteers that have experience choosing or not choosing growth hormone therapy.