Diseases & Conditions
In Turner's syndrome (gonadal dysgenesis), girls are born with one of their two X chromosomes partially or completely missing. Turner's syndrome is caused by the deletion of or partial formation of one of the two X chromosomes. Girls with the syndrome have a short stature, loose skin on the back of the neck, learning disabilities, and an inability to undergo puberty. The diagnosis is confirmed by analyzing the chromosomes. Treatment with hormones can stimulate growth and initiate puberty.
Turner's syndrome occurs in about 1 out of 4,000 live female births and is the most common sex chromosome abnormality in females. However, 99% of affected fetuses abort spontaneously.
Many newborns with Turner's syndrome have swelling (lymphedema) on the backs of their hands and tops of their feet. Swelling or loose folds of skin are often evident over the back of the neck. Other abnormalities often develop, including a webbed neck (wide skin attachment between the neck and shoulders) and a broad chest with wide-spaced nipples. Affected girls have a short stature compared with family members. Less common symptoms include drooping upper eyelids (ptosis), a low hairline at the back of the neck, moles (nevi), and poorly developed nails.
Girls with Turner's syndrome generally do not have menstrual periods (amenorrhea), and the breasts, vagina, and labia remain childlike rather than undergoing the changes of puberty. The ovaries usually do not contain developing eggs. A girl or woman with Turner's syndrome is virtually always short, and obesity is common.
Other disorders often develop. Heart defects include narrowing of part of the aorta (coarctation of the aorta—see Birth Defects: Coarctation of the Aorta ). Kidney defects, diabetes mellitus, and thyroid diseases are common. Occasionally, abnormal blood vessels in the intestine cause bleeding. Hearing loss occurs, and crossed eyes (strabismus) and farsightedness (hyperopia) are common. Celiac disease occurs more frequently in girls with Turner's syndrome than among the general population.
Many girls with Turner's syndrome have attention-deficit/hyperactivity disorder and learning disabilities with difficulty assessing visual and spatial relationships, planning tasks, and paying attention. They tend to score poorly on certain performance tests and in mathematics, even if they achieve average or above-average scores on verbal intelligence tests. Mental retardation is rare.
A doctor may suspect the diagnosis because of the newborn's abnormal appearance. However, they may not suspect the syndrome until the teenage years, when the girl has a short stature and does not mature sexually. Analysis of the chromosomes confirms the diagnosis.
Treatment with growth hormone can stimulate growth. Estrogen replacement therapy is usually needed to initiate puberty and is typically given at age 12 to 13. Treatment with the female hormone estrogen is usually not started until after satisfactory growth has been achieved. Estrogen treatment may improve the girl's ability to plan tasks, pay attention, and assess visual and spatial relationships as well as stimulate sexual maturation. Children with this syndrome should have regular hearing exams, an eye exam by a pediatric ophthalmologist, regular thyroid function tests, and a screening test for celiac disease.
Last full review/revision December 2008 by Gregory S. Liptak, MD, MPH
Source: The Merck Manual Home Edition