Growth and Growth Hormone Therapy 
 

Short stature is one of the most common and easily recognizable features of Turner syndrome (TS), with an average adult height being 4’8”, without growth hormone (GH) treatment.  Those with TS produce growth hormone but their bodies don’t respond to it effectively. Those with a mosaic form of TS have growth failure yet their height is more variable.

 

  • Before birth growth failure may be noticed on an ultrasound

  • By 3.5 years of age, growth failure is often significant. Most (75%) of 3.5-year-olds with TS are 95% shorter than other girls the same age.

  • Around 4-6 years of age, it is recommended to begin GH therapy (or earlier if growth failure is already noticeable) and continue therapy until satisfied with final height or until little growth potential remains.

  • Around 11-12 years of age it is recommended to initiate puberty with estrogen replacement therapy. Generally, those with TS will not have a pubertal growth spurt even if they develop puberty on their own.  Puberty speeds up bone growth and maturation.  Despite this, the recommendation is to move forward with estrogen replacement but adjust the way estrogen is taken, its dosage, and the speed at which the dose is increased in order to promote the best possible growth and adult height. An endocrinologist will help you determine what the best balance is for growth and sex-hormone replacement.  

  • 15 years of age or so, growth plates of the bones fuse together and physical growth stops. Most with TS have a delayed bone age, meaning the bones grow slower than others the same age, thus increasing the potential to grow for a longer period of time.

What is growth hormone?

Natural human growth hormone (HGH) is produced by the pituitary gland within the brain.

  • It supports muscle and bone growth and possibly heart function

  • regulates body composition

  • regulates body fluids

  • regulates sugar use

  • regulates fat metabolism

  • stimulates the liver to produce IGF-I (insulin-like growth factor I) important for bone growth.

 

What is growth hormone therapy?

A biosynthetic form of HGH (made in a laboratory) is available for medical use and approved by the FDA for treatment of short stature 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.

What if someone with TS doesn't have growth hormone therapy?

GH therapy is optional and a personal decision. Studies on TS suggest height is not a predictor of life satisfaction. Women with TS who have not had GH therapy reach heights from 4’6-5’3” with mosaic TS related to the latter heights. Women with TS of all heights often mention the same challenges and accomplishments.  

How does the GH therapy process work?

A pediatric endocrinologist prescribes GH medication and contacts 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. If you struggle to receive insurance approval, askTSSUS for help.

 

Although there are many GH companies, the medications are quite similar, the injection device is the main difference.  Review and report side-effects to the endocrinologist.

 

GH is injected, as a shot, into the fatty tissue of either the thigh, stomach, hip, or back of the arm every day. The shot comes in various devices that are easy to use and allow you to dial the medication amount. They use short needles and a nurse will teach you all about the process. You’ll become a pro at giving the shots (really!) and your daughter should adapt quickly too. If you need additional support you can contact us at TSSUS and talk to other parents too.

 

  • Often the thought of getting a shot is scarier than the pain of the shot itself.

  • Some girls prefer shots to be given when they are asleep (ask permission from them first)

  • Celebrate growth with new shoes, clothing, and a height chart at home 

  • Allow your daughter to watch videos of other girls getting their shots and remind them how brave they are.

  • The initial dose is recommended at 0.375 mg/kg/week or 0.05 mg/kg/d (for the U.S.)

  • It is not recommended to add a 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 dosage is based on weight, how the body utilizes the hormone and insurance coverages. The TSSUS office or your doctor can help you understand the options available to you. Some pharmaceutical companies offer patient assistance programs to help obtain approval for coverage or financial assistance.  It’s confusing to list 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.

The information provided is based on the TS Clinical Practice Guidelines for the Care of Women and Girls with TS and reviewed by a TSSUS medical advisor in 2021.

Growth in Turner Syndrom Turner Topic TSSUS

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 for increased adult height in TS.

 

Growth Comparison Charts​

 

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.:

 

TSSUS is here to help answer other questions you may have, contact us at 1-800-365-9944 or info@turnersyndrome.org. We 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.

Turner Syndrome Growth Chart TSSUS
Turner Syndrome a Guide for Families TSSUS