Pharmacotherapy of Turner syndrome (TS) is a hormonal therapy, which is used as an adjuvant treatment of Turner syndrome. At various ages, different medical problems are the focus of treatment.
Short stature is diagnosed in the majority of TS patients. Without medical intervention, the final height is 20 cm below normal range. The growth-promoting therapy is based on the usage of growth hormone (GH) therapy. In some older patients (9 years) with very poor prognosis of final height, the addition of a low dose of oxandrolone (anabolic steroid) should be considered. The addition of oxandrolone to GH treatment may increase adult height by even more than 4 cm.
Another typical feature of TS patiens is gonadal dysgenesis (congenital developmental disorder of the reproductive system characterized by a progressive loss of germ cells on the developing gonads of an embryo) is diagnosed in most TS patients; however, more than 30 % of girls with TS present some symptoms of puberty, especially patients with mosaic (a presence of healthy and affected cells in the body) karyotype. The mean age for estrogen therapy is 12 to 14 but low-dose treatment can be started even in younger girls. Puberty should be initiated by using low-dose transdermal (application across the skin) estrogens, although the optimal formulation, dosage and route of administration are still under dispute. Estrogen replacement therapy (ERT) has been shown to have several beneficial effects including age-appropriate development of secondary sexual characteristics (features that appear during puberty in humans, such as pubic hair, enlarged breasts in females), improved psychosocial functioning, increased bone mineral density and better uterine development.
Spontaneous pregnancy is possible in only 2 % of TS women. The preparation of a TS patient for pregnancy, either spontaneous or by in vitro fertilisation (IVF), should include a risk assessment of potential pregnancy-related complications in TS. Beside the regular thyroid function and glucose tolerance tests, cardiovascular and renal system evaluation is also recommended.
As indicated previously, one of the most common clinical features among individuals with TS is short stature. Growth hormone is typically prescribed to children with TS in order to increase final height. Girls with TS who were treated with GH for one year were significantly taller than those who did not receive GH. Studies suggest that GH treatment can result in achievement of normal adult height, and starting GH at an early age (4–6 years) appears to be a factor in the success of the treatment. The effects of GH on height can diminish after the first 1–2 years of administration and therefore an escalating dosage schedule is often required, with higher doses in adolescence.
Positive predictive markers (a particular protein or gene that indicates sensitivity or resistance to a specific therapy) of good response to GH include tall height at therapy onset, taller parents, better first-year responsiveness to GH, higher GH doses and longer time of therapy.
Estrogen replacement therapy is currently the standard treatment for estrogen deficiency/insufficiency. ERT should ideally be started around the age of 12 or at an age consistent with pubertal development in the patient’s peers to decrease psychosocial distress ERT should be initiated also with consideration of GH therapy. Some reports have indicated that ERT can reduce final adult height in patients being treated with GH. However, more recent studies indicate that the use with an increasing dosage schedule may reduce ERT’s affect on height attainment.
Some clinicians have expressed concerns that GH treatment may result in undesirable changes to body proportions such as enlarged feet and hands in adolescents. Further research is needed in this area. Researchers also warn treatment providers to be wary of psychosocial problems related to weight management issues in TS. However, GH treatment may result in increased lean body mass and decreased body fat thus improving physical health associated with body composition.
GH does not affect bone mineral density but may increase the risk of otitis media and certain joint disorders. GH decreases insulin sensitivity which, in combination with a tendency towards greater adiposity in TS, may contribute to development of type 2 diabetes. However, insulin resistance tends to decrease after approximately 7–8 years of GH therapy and returns to normal after GH therapy is discontinued.
It is unclear whether or not GH therapy affects cognitive function in girls with TS. Very few studies examining this relationship have been conducted. One small but very well designed study indicated no influence of GH on cognitive function in females with TS.
In conclusion, recombinant human GH therapy in combination with estradiol starting at the normal age of puberty is the treatment of choice for the treatment of short stature in girls with TS. Growth hormone therapy seems to be safe, with no adverse effects so far, on glucose metabolism or cardiac function or any association with neoplasms (a tumour mass), but further studies are needed to give conclusive data on the issue of long-term safety.
No cure for Turner syndrome is known. Treatment, however, may help with symptoms. Human growth hormone injections during childhood may increase adult height. Estrogen replacement therapy can promote development of the breasts and hips. Modern reproductive technologies have also been used to help women with Turner syndrome become pregnant if they desire. For example, a donor egg can be used to create an embryo, which is carried by the Turner syndrome woman.
Medical care is often required to manage other health problems with which TS is associated witch, such as cardiovascular diseases, ovarian failure, osteoporosis, hearing loss, diabetes mellitus and hypothyroidism.
The goal of pharmacotheraphy of TS patient is to maximise her lifelong functioning. It is vital that the services continue uninterrupted throughout the transition period (as the patient moves from adolescence to adulthood). TS patients require lifelong high-quality and developmentally adequate healthcare. Early diagnosis and cooperation of a multidisciplinary team familiar with TS-related health problems are essential for successful patient management.