Your browser does not support javascript:   Search for gard hereSearch for news-and-events here.


Genetic and Rare Diseases Information Center (GARD)

Print friendly version

Turner syndrome

Other Names for this Disease
  • 45, X Syndrome
  • Bonnevie-Ulrich syndrome
  • Chromosome X Monosomy X
  • Gonadal Dysgenesis (45,X)
  • Schereshevkii Turner Syndrome
More Names
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

I recently learned that my daughter has a karyotype of 45,X/46,XY, consistent with mosaic Turner syndrome. The only sign she has is mild clitoromegaly. Can you give me general information about mosaic Turner syndrome and about the prognosis of this condition?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What are the signs and symptoms of Turner syndrome?

There are various signs and symptoms of Turner syndrome, and they can range from very mild to more severe among individuals with the condition. Girls who have Turner syndrome are typically shorter than average. They often have normal height for the first three years of life, but then have a slow growth rate. In early childhood, individuals may have frequent middle ear infections, which can lead to hearing loss in some cases. At puberty, they do not have the usual growth spurt, and the ovaries do not function properly (they do not begin to produce sex hormones). Therefore, most girls with Turner syndrome do not start their periods or develop breasts without hormone treatment. Although most individuals with Turner syndrome are infertile, the vagina and uterus are usually normal. Individuals with Turner Syndrome usually have normal intelligence with good verbal skills and reading skills. Some girls, however, have problems with math, memory skills and fine-finger movements.

Additional symptoms of Turner syndrome may include a very wide neck (webbed neck) and a low or indistinct hairline; broad chest and widely spaced nipples; arms that turn out slightly at the elbow; heart murmur, sometimes associated with narrowing of the aorta (blood vessel exiting the heart); tendency to develop high blood pressure; and minor eye problems that may be corrected by glasses. Scoliosis (curving of the spine) occurs in 10 percent of adolescent girls who have Turner syndrome. Additionally, the thyroid gland becomes under-active in about 10 percent of women with the condition. Older or over-weight women with Turner syndrome are slightly more at risk of developing diabetes. Osteoporosis can develop due to a lack of estrogen, but this can usually be prevented by taking hormone replacement therapy.[1]
Last updated: 12/15/2010

What is mosaic Turner syndrome?

In Turner syndrome, an individual does not have the usual pair of two complete X chromosomes. The most common scenario is that a girl has only one X chromosome in all of her cells. However, some girls with Turner syndrome have a full or partial absence of the X chromosome in only some of their cells.[1] When an individual has a different chromosomal content in his/her cells, it is called mosaicism. When some of the cells have one X chromosome and no other X or Y chromosome, and other cells have either the usual two sex chromosomes (two X's or one X and one Y) or other chromosomal differences, it is called mosaic Turner syndrome. Mosaic Turner syndrome, like Turner syndrome, is not typically inherited. It occurs as a random event during cell division in early fetal development. Other sex chromosome abnormalities are also possible in individuals with X chromosome mosaicism.[2] Mosaicism of both the X and the Y chromosome is a common finding in Turner syndrome.[3]

The features of mosaic Turner syndrome can vary considerably from individual to individual. In females, they can range from mild to severe signs and symptoms of Turner syndrome. In males, they can range from a seemingly normal male to the presence of a variety of features which can include dysmorphic (abnormally formed) features, mild intellectual disabilities, infertility, Ulrich-Turner stigmata (drooping of upper eyelid, extra “webbing” on the neck), gonadal dysgenesis, infertility, low testosterone levels, and azoospermia (having no sperm).[4]
Last updated: 7/26/2011

What is the prognosis for individuals with Turner syndrome?

Overall prognosis for individuals with Turner syndrome is typically good. Even with growth hormone therapy, most individuals are shorter than average. Life expectancy is slightly shorter than average but may be improved by addressing associated chronic illnesses, such as obesity and hypertension. Almost all individuals are infertile, but pregnancy with donor embryos is possible.[5]

There is limited information specific to the general prognosis for individuals with mosaic Turner syndrome; this may be due to the fact that there are several types of mosaic Turner syndrome, and signs and symptom of the condition can vary widely.
Last updated: 12/15/2010

What might be expected if an individual has mosaic Turner syndrome with a 45,X/46,XY karyotype?

There is wide variation in features that have been reported in individuals with a 45,X/46,XY karyotype (a form of Turner syndrome mosaicism). Studies have reported that 90 percent of individuals diagnosed before birth (prenatally) have normal male appearance at birth, while those diagnosed after birth (postnatally) show a wide spectrum of features, ranging from "classic" Turner syndrome, mixed gonadal dysgenesis (the presence of some male structures as well as a uterus, vagina, and fallopian tubes), and male pseudohermaphroditism (genitalia are of one sex, but some physical characteristics of the other sex are present) to apparently normal male. There may be a risk for late-onset abnormalities, such as testicular problems leading to infertility or cancer, and short stature, which could be improved with growth hormone therapy.[6] Classic Turner syndrome features seem to be the most common features. Mild intellectual disabilities and signs of autism have also been reported.[7]
Last updated: 7/26/2011

How can I find a genetics professional in my area?

Genetics clinics are a source of information for individuals and families regarding genetic conditions, treatment, inheritance, and genetic risks to other family members. More information about genetic consultations is available from Genetics Home Reference. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral.

The following online resources can help you find a genetics professional in your community:
Last updated: 10/18/2013