Child Health
Our delayed puberty guide mentions Turner syndrome as one cause of a short girl who hasn't started puberty, and our growth hormone therapy guide lists it among the conditions GH is approved for. This piece focuses on Turner syndrome itself and what it means for height: why girls with the condition are short, why early diagnosis matters, how much growth hormone actually adds, how puberty is managed without costing height, and why height is only one part of good care.
How Much Height Does Growth Hormone Add in Turner Syndrome?
Average adult height gains reported in randomized trials and summarized in the 2024 guidelines
What Turner Syndrome Is
Girls with Turner syndrome have one intact X chromosome and are missing all or part of the second. The most common forms are 45,X, a mosaic pattern (45,X/46,XX), or a structural change in one X.
Besides short stature, the condition often affects the ovaries, and can involve the heart, kidneys, hearing, and learning. Girls with the mosaic form tend to have milder features.
The short stature in Turner syndrome is closely tied to a gene called SHOX, short for "short stature homeobox." It sits on the tip of the X and Y chromosomes, and most people have two working copies. In 1997, researchers identified SHOX and linked the loss of one copy to growth failure, both in Turner syndrome and in some children with otherwise unexplained short stature. That's why some genetic findings discussed in our idiopathic short stature guide overlap with Turner syndrome. Importantly, the short stature isn't caused by the delayed puberty that often accompanies the condition. The two simply occur together.
Why Early Diagnosis Matters for Height
Growth slowing in Turner syndrome starts before birth and worsens in the first years of life, so every year without a diagnosis is a year of lost growth potential. Yet the 2024 guidelines describe missed and delayed diagnoses as a major ongoing problem.
Sometimes suspected on prenatal scans or screening
Swollen hands or feet, a heart defect, or other features
Short stature becomes obvious or puberty doesn't start
Absent periods or fertility questions lead to testing
Those four windows are when Turner syndrome is most often diagnosed, according to the guidelines. The practical point for parents is that a girl who is clearly short without an explanation should have her chromosomes checked, even if she has none of the other physical features. Other reasons to test include unexplained delayed puberty or missing periods, certain left-sided heart defects, and combinations of features such as kidney abnormalities, early hearing loss with short stature, or characteristic facial or neck features. Our guide on when to worry about a child's height covers the broader warning signs.
Growth Hormone: What It Can and Can't Do
Growth hormone has been FDA-approved for Turner syndrome since 1996. The 2024 guidelines recommend offering it early, because early treatment can prevent further loss of height potential, and say it may be offered from as young as 2 years of age when there's growth failure, short stature, or a likelihood of short stature.
In the Canadian randomized trial, girls who received growth hormone reached an average adult height of 147.5 cm (4 ft 10 in), compared with 141.0 cm for untreated girls, a gain of about 7.2 cm, though responses varied a lot from girl to girl. The guidelines add that if a child catches up into the normal range within the first 2 years of treatment and keeps growing well, an adult height of about 152 cm (5 ft) is possible. Factors linked to a taller result include being taller when treatment starts, having taller parents, starting younger, spending more time on treatment before puberty, and the dose used. Response is usually tracked by measuring height every 4 to 6 months.
What growth hormone doesn't change. A follow-up of young women from the Canadian trial found no benefit or harm to health-related quality of life from having received growth hormone, consistent with larger observational studies. That doesn't make treatment pointless, since the guidelines frame its goal as reaching a height that reduces practical and social limitations and lets puberty start at an age similar to peers. But it's a useful reminder that height is one part of how girls with Turner syndrome fare, not the whole story. The guidelines also note that safety has been reassuring overall, with a higher risk of increased pressure around the brain and of a hip growth-plate problem than in other children on GH. These are rare but serious, and scoliosis, which is common in Turner syndrome, can worsen during treatment.
A few related questions come up often. The 2024 guidelines do not recommend routinely adding very low-dose estrogen in the years before puberty to boost growth. The patient version of the guidelines notes that oxandrolone, an add-on once used in some programs, is not recommended and isn't available in the U.S. And weekly long-acting growth hormone, now used for children with GH deficiency as our GH therapy guide describes, was still awaiting approval for Turner syndrome when the guidelines were published.
Puberty, Estrogen, and Protecting Height
Most girls with Turner syndrome need estrogen replacement to go through puberty, because the ovaries stop working early. About 15% have spontaneous periods, more often those with the mosaic form. Timing and dosing are planned carefully because estrogen also signals the growth plates to close.
The Canadian trial's conclusion supports this approach: growth hormone combined with puberty induced at a near-normal age increased adult height. Estrogen also matters well beyond height, supporting breast development, periods, uterine health, and strong bones.
Height is one item on a longer checklist. About half of girls with Turner syndrome have a congenital heart difference, structural kidney differences affect 18% to 60%, and hearing loss, thyroid problems, and celiac disease are more common. Many girls also have specific learning differences, especially with math and visual-spatial skills, though most have average intelligence. That's why the guidelines recommend care in a specialist multidisciplinary clinic alongside the regular pediatrician, with scheduled heart, kidney, hearing, and developmental checks.
What This Means For You
The practical takeaway: short stature is the most consistent feature of Turner syndrome, and without treatment most girls end up about 20 cm below their expected height. Growth hormone, ideally started early, typically adds about 5 to 8 cm, and well-timed, gradually increased estrogen helps protect that height while supporting normal puberty. Because Turner syndrome affects more than growth, the best results come from specialist, multidisciplinary care. For how growth hormone works more generally, see our GH therapy guide, and for other reasons a girl's puberty may be late, see our delayed puberty guide.
Frequently Asked Questions
How tall do girls with Turner syndrome get?
Without treatment, girls with Turner syndrome typically end up about 20 cm below their expected adult height. In a Canadian trial, untreated girls averaged 141 cm (4 ft 7.5 in) as adults, while girls treated with growth hormone averaged 147.5 cm. The guidelines note that an adult height of about 152 cm (5 ft) is possible for girls who respond well early in treatment.
Why are girls with Turner syndrome short?
Largely because they have only one copy of the SHOX gene, which sits on the sex chromosomes and is important for bone growth. Growth slows before birth and falls further behind in early childhood. The short stature isn't caused by the delayed puberty that often accompanies the condition; the two occur together.
How much does growth hormone help in Turner syndrome?
Randomized trials followed to adult height found average gains of about 7.2 cm in Canada and 5.0 cm in the U.S., and the 2024 guidelines describe typical gains of 5 to 8 cm. Starting younger, spending longer on treatment before puberty, and being taller at the start are linked to better results.
When should growth hormone start for Turner syndrome?
Early. The 2024 international guidelines recommend offering growth hormone early because growth failure begins before birth and is rapid in the first years of life. Treatment may be offered from as young as 2 years of age when there's growth failure, short stature, or a likelihood of short stature.
Does estrogen treatment affect height in Turner syndrome?
It can, which is why it's started carefully. The guidelines recommend beginning low-dose estrogen at 11 to 12 years when tests show puberty won't start on its own, then increasing it slowly over 2 to 4 years. Low starting doses help preserve remaining height while allowing puberty to begin at an age similar to peers.
