Definition of Turner Syndrome
Turner syndrome is a chromosomal abnormality in females. There is either absence of an entire X chromosome or abnormalities in one of the two sex chromosomes (normally there are 46 chromosomes of which two are sex chromosomes, either XX in females or XY in males). It is named after Henry Turner, the endocrinologist who first described it.
Cause of Turner Syndrome
The cause of Turner syndrome is the absence of one X chromosome in some or all the cells. The abnormal cells have only one healthy and complete X chromosome (monosomy) or there may be partial monosomy. Deletion of short arm of X chromosome or isochromosome with two q arms are the examples of partial monosomy.
Inheritance is the most important cause of Turner syndrome. Most of these cases are due to nondisjunction of the sex chromosome in the father and the only X chromosome present in the patient comes from the mother. These are called the meiotic errors. The incidence of Turner syndrome is sporadic and the risk of recurrence is not high in subsequent pregnancies.
Signs and Symptoms Turner Syndrome
The signs and symptoms of Turner syndrome are many. These are:
Swelling of the hands and feet
Broad chest and widely spaced nipples
Ears are low-set
Absence of menstrual cycle
Characteristic facial features
Aortic valve stenosis
Coarctation of aorta
Bicuspid aortic valve
Nonverbal learning disability
Attention Deficit/Hyperactivity Disorder
Risk Factors for Turner Syndrome
There are no known risk factors of Turner syndrome. It happens mostly in females. Even the family history doesn’t seem to play role in the development of Turner syndrome as it is unlikely for the parents with one child having Turner syndrome to have another child with the same disorder.
Diagnosis of Turner Syndrome
The diagnosis of Turner syndrome can be made prenatally (before birth) and/or postnatal (after birth):
The diagnosis can be made through amniocentesis or chorionic villus sampling during pregnancy.
Ultrasound findings may reveal abnormal development of the fetus e.g. heart defect, kidney abnormalities, cystic hygroma, ascites, etc.
After birth, it can be diagnosed at any age. Heart abnormalities, wide neck or swelling of the hands and feet are the earliest signs at birth. Short stature and primary amenorrhea are the classic signs of Turner syndrome.
Chromosomal analysis (also called the karyotype) of the suspected individual could be done to find the abnormality in the chromosomes. It is the test of choice for the diagnosis of Turner Syndrome.
Treatment of Turner Syndrome
As Turner syndrome is a chromosomal abnormality, little can be done for its cure. However efforts are made to minimize the symptoms.
Growth hormone is used either alone or in combination with androgen to deal with the problem of short stature. There is evidence that this combination is effective in growth and attainment of adult height.
Estrogen replacement therapy.
Estrogen replacement therapy has been used for the development of secondary sex characteristics. Estrogens play a key role in the maintenance of bone density, cardiovascular health and tissue health. Turner syndrome patients, if not treated with estrogen, are at an increased risk of developing osteoporosis and heart conditions.
Modern reproductive technologies.
If a Turner syndrome patient wishes to become pregnant, then modern reproductive techniques may be helpful. In this case, a donor egg is used to create an embryo. This embryo is then implanted in the uterus of a patient with Turner syndrome.