A disorder in women caused by a chromosomal defect. This disorder inhibits sexual development and causes infertility .
Alternative Names
Bonnevie-Ullrich syndrome; Gonadal dysgenesis; Monosomy X
Causes, incidence, and risk factors
Turner syndrome is usually caused by a missing X chromosome. It affects 1 out of 3,000 live births. It is usually sporadic meaning that it is not inherited from a parent. Rarely, a parent silently carries rearranged chromosomes that can result in Turner syndrome in a daughter; this is the only situation in which Turner syndrome is inherited. There are many manifestations of this syndrome, but the main features are short stature , webbing of the skin of the neck, absent or retarded development of secondary sexual characteristics, absence of menstruation, coarctation (narrowing) of the aorta, and abnormalities of the eyes and bones. The condition is either diagnosed at birth because of the associated anomalies, or at puberty when there is absent or delayed menses and delayed development of normal secondary sexual characteristics.
Signs and tests
A physical examination reveals underdeveloped breasts and genitalia, webbed neck, short stature , and abnormal development of the chest.
Karyotyping shows 45 chromosomes with a pattern 45 X,0 i.e. a missing sex chromosome. Ultrasound may reveal small or underdeveloped female reproductive organs. Gynecologic exam may reveal dry vaginal lining. Serum luteinizing hormone is elevated. Serum follicle stimulating hormone is elevated. This disease may also alter the results of the following tests:
estriol - urine estriol - serum estradiol - test
Treatment
Treatment is supportive. Growth hormone replacement may or may not be prescribed; it may help the child to achieve a more "normal" height. Estrogen therapy is started at 12 or 13 years old to stimulate the development of secondary sexual characteristics so that girls affected with this disorder will have a more normal appearance as an adult. Estrogen therapy, however, will not reverse infertility . Vaginal lubricants may prevent dryness, itching and pain during intercourse. Cardiac surgery is sometimes necessary to correct heart defects.
Expectations (prognosis)
This chromosome abnormality is associated with numerous medical conditions and problems in addition to the lack of sexual maturity. In the absence of severe heart defects at birth women survive into adulthood with normal intelligence. Some patients with Turner syndrome have experienced stigmatization at being short, having underdeveloped sexual characteristics, avoiding painful intercourse or not being able to produce children.
Prevention
There is no known prevention for this inherited disorder after birth. If prenatal amniocentesis karyotype (chromosome analysis) shows a missing X chromosome parents may decide to end the pregnancy.