Turner Syndrome: A genetic disorder unique to women
What is Turner Syndrome?
Turner syndrome is a female-only genetic disorder that affects approximately 1 in every 2,000 baby girls. Usually, females have two X sex chromosomes (‘XX’), however, girls born with Turner syndrome may only have one X chromosome (classic Turner syndrome) or two X chromosomes with one X chromosome being partly missing/incomplete (mosaic Turner syndrome). The chromosome variation occurs randomly during conception and is not linked to the age of the mother. The syndrome received its name from Dr Henri Turner, an American endocrinologist, who in 1938, described 7 female patients with similar physical features that are now associated with the syndrome.
What are the characteristics of Turner Syndrome?
The characteristics of women with Turner syndrome are varied, with almost all girls being shorter than average by approximately 20 cm. For those affected, the ovaries are underdeveloped, and women are likely to experience infertility and a lack of menstruation. Other characteristics include a ‘webbed’ neck, a low hairline, hearing loss, droopy eyelids, and low-set ears. Various comorbidities are associated with Turner syndrome including diabetes, scoliosis, urinary tract infections, hypertension, and osteoporosis. In addition, some girls with the syndrome may have issues with spatial awareness, understanding social relationships, and experience hyperactivity.
If like me, you had not heard of the syndrome before, you are not alone. There is a lack of governmental engagement and funding associated with the condition. This suggests that those in power are not doing enough to engage with patients to improve their quality of life and lower the burden of disease.
The National Institute for Health and Care Excellence (NICE) published guidance over 11 years ago for the use of the human growth hormone (somatropin) for the treatment of girls with Turner syndrome. However, since then, public, and governmental engagement for the condition has been severely lacking.
What are the treatment options for Turner Syndrome?
Unfortunately, there is no cure. Girls with Turner syndrome are entitled to receive daily high‑dose injections of growth hormone therapy as soon as it is apparent that the growth rate is slow. This can start as early as 5 years of age and can continue until 15 years of age. Studies have shown that the use of somatropin significantly increases height between treated and untreated girls with Turner syndrome by approximately 5 cm. Of note, girls with Turner syndrome do not have a growth hormone deficiency but may have lower sensitivity to growth hormones, a result of the haploinsufficiency of the short stature homeobox‑containing gene. Hence, not all women with Turner syndrome require somatropin treatment.
Oestrogen and progesterone replacement therapy are required until menopause to allow girls to undergo normal development associated with puberty and to begin menstruation. Girls are typically started on oestrogen therapy at 10–12 years of age, increasing in dose over time to mimic puberty. Progesterone replacement therapy is administered after oestrogen therapy and induces menstruation.
Only a minority of women with Turner syndrome can conceive naturally, and for women that do become pregnant, regular cardiac checks are required throughout pregnancy to monitor the impact of the condition on the heart.
Alongside the physical implications, psychological therapy can be offered in the form of counselling and cognitive behavioural therapy (CBT) to help support women with this lifelong condition.
Due to the comorbid nature of patients with Turner syndrome, it is vital that regular health checks are made to ensure that not only is Turner syndrome managed appropriately but those associated conditions (diabetes, osteoporosis, etc.) are also managed. This can include regular blood pressure checks, testing of glucose levels for diabetes, measuring bone mineral density, or testing of thyroid function due to the risk of hypothyroidism. Patients with Turner syndrome are therefore treated by a multidisciplinary team. The clinical team will automatically opt patients into the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS) to provide the NHS data to allow optimisation of healthcare services to support women with Turner syndrome.
What about future treatments for Turner Syndrome?
Despite there being no new therapies for Turner syndrome, this is not a reason to give up hope. Research is underway to investigate the following: the dose-response relationship of somatropin with height, identification of predictive markers after one month of somatropin therapy in girls with Turner syndrome, use of genetic profiles to determine the response to recombinant human growth hormone and identifying the optimal monitoring process for patients treated with somatropin.
Women with Turner Syndrome face lifelong burdens
If Turner syndrome only affects women and is relatively rare, why should we care? This is a lifelong condition, with a shorter life expectancy than average (approximately 70 years). One study determined the mortality rate in women with Turner syndrome to be 3-folds higher than the general population. Females with Turner syndrome also have increased mortality due to pneumonia, diabetes, epilepsy, liver, or kidney disease. The management of Turner syndrome can place a large burden on girls and their families, for example, daily injections are required from approximately 5–15 years of age and oestrogen and progesterone treatment is required until menopause. Due to the significant comorbidities, patients require consistent follow-up and screening to monitor the possible complications and care by a multidisciplinary team.
Who can help?
The UK-based Turner Syndrome Support Society (TSS) offers support, advice, and information to women with Turner syndrome and their families. Please find their services here: https://tss.org.uk/. To raise awareness of the condition, 21st June is marked on the calendar as Turner syndrome awareness day.
The symptoms associated with a missing (or partially missing) X sex chromosome are varied and chronic. The implications on normal pubescent development must be appropriately managed, and careful consideration should be made to ensure that comorbidities are checked and treated as required. Turner syndrome is undoubtedly underfunded, under-researched and consequently, not well understood. I hope this article shines a light on the condition, adding to the conversation on the effect of Turner syndrome on a female’s quality of life and helps provoke much-needed further research into girls living with Turner syndrome.
Medical Writer II & Project Coordinator