Turner syndrome is a rare genetic disease that afflicts only females. It usually affects multiple organs. There are 23 pairs of chromosomes (=46 chromosomes; 45, XX, or XY) within each cell of the body and in Turner syndrome, one chromosome in the form of a sex chromosome called the X chromosome is either missing completely (45, XO) or partially, with loss of certain functions. Mosaicism (the abnormal genetic event in which a body’s cells have different sets of chromosomes) is another condition of the body that leads to Turner syndrome.
The prevalence of Turner syndrome is 1 in 2,000-2,500 live female births. Unfortunately, due to the delayed diagnosis of Turner syndrome, there has been an adverse impact on age-related milestones in females as their age progresses. The patients show impaired sexual function, and almost half of the patients show sexual inactivity. In adolescent females, the disease often manifests with delayed puberty, secondary to premature ovarian failure. The typical feature is ‘streak gonads’, which is a form of absence of cells in the tissue. Turner syndrome was first defined and described by Oklahoma physician Henri Turner in 1938.
Turner syndrome patients have an increased risk of complications and comorbidities such as cardiovascular malformations, diabetes, pulmonary or lung-related venous abnormalities, and coronary artery diseases. Patients with Turner syndrome also show an inclined death rate due to pneumonia, epilepsy, liver disease, as well as kidney disease.
The current literature emphasizes the fact that three dominant countries are coming up with epidemiological studies and figures which are Denmark, the U.K., and Sweden in perspective of sex chromosome abnormalities including Turner syndrome. The prevalence of TS is approximately 1 in 2000 females on average, globally. Now, there is also a newborn prevalence of 59 in 100,000.
In India, most females are left undiagnosed with this abnormality, and even when diagnosed, most people are not followed up regularly. Considering the birth rate of females in proportion to the population of India, with an annual incidence of roughly 1 in 2500 female births diagnosed with TS, the number of annual cases count to 5,200 females. The Indian median age of TS at diagnosis was estimated to be 12 years. Studies found that even if congenital cardiac complications due to TS was factored out, the life span of TS patients is reduced substantially in comparison to healthy individuals.
Signs and symptoms
The symptoms vary as the age progresses. Typically, in the female newborn, Turner syndrome can manifest with congenital lymphedema of the extremities of the body such as hands and feet, dysplasia of nails or presence of abnormalities within nail tissue, webbed neck, broad chest with widely spaced nipples, narrow and high-arched palate ( a narrow, tall roof of the mouth or the hard palate), and short fourth metacarpals or metatarsals, hearing loss, kidney dysfunction, and eye or vision-related abnormalities are common associative manifestations of Turner syndrome.
A prenatal diagnosis of this genetic disease relies heavily on the sampling of chorionic-villus or amniocentesis. A karyotype analysis should also be done with peripheral blood mononuclear cells. If the initial karyotype testing does not indicate Turner syndrome, a second karyotype should be performed utilizing a different tissue sampling such as dermal tissue, bladder epithelial tissue, or buccal mucosa tissue sampling. Fluorescence in-situ hybridization (FISH) study is an option in addition to the karyotype, which can detect abnormality in part of the DNA sequence or chromosomes regarding missing chromosomal material. Other than karyotyping and FISH, MRI, ultrasonography, and cardiovascular evaluation along with marker tests of hormones AMH and TSH levels should be employed for confirmation of the disease.
Management comprises age-appropriate treatment of the symptoms, complications, and comorbidities of Turner syndrome, to improve the quality of life of the patients. Growth hormone therapy is the most promising therapy along with estrogen therapy in Turner syndrome.
To encourage fertility preservation, all Turner syndrome women should be evaluated in childhood. Preservation is needed early in life as the majority of women will have their ovarian reserve exhausted before adulthood due to the disease. Growth hormone therapy can occasionally expose underlying scoliosis (a condition defining a one-sided curvature of the spine frequently diagnosed in adolescents). Hence, the patients should be monitored closely every six months, regarding the position of their spines during the treatment and if needed, they should consult an orthopedic surgeon for possible corrective surgery.
Quality of life
Quality of life-related complications with patients taking necessary growth hormone therapy are adverse effects of intracranial hypertension, pancreatitis (inflammation of the pancreas), and slipped capital femoral epiphyses (a condition defining rearrangement of bones on hip joints during teens and pre-teens years of growth). If the patient happens to need further assistance for growth even after administration of growth hormone, oxandrolone may be administered, or pubertal induction can be presented.
Support groups recommend the use of Turner syndrome-specific transition tool kits such as the one improved by the Endocrine Society, Hormone Health Network, and Turner Syndrome Society of the U.S.A., specifically the American College of Physicians Pediatric to Adult Care Transitions toolkit. For best care, it is recommended that dual-energy X-ray absorptiometry or DXA scans for at least 5 years along with continued estrogen supplementation until ordinary menopausal age should be done; it can also manage bone health in women with Turner syndrome. Adequate counseling in adult Turner syndrome clinics should be performed for psychosocial issues, career options and sustenance, sexual function, contraception, fertility options as well as interpersonal relationships.