Turner syndrome (TS) is the result of a chromosomal abnormality in which all or part of one of the X chromosomes is missing or altered in females. It is a genetic condition that affects development in only females.
Turner syndrome is one of the most common chromosomal abnormalities, occurring in approximately 1 in 2,000 to 2,500 live-born female infants worldwide, but it is much more common among pregnancies that do not survive to term (miscarriages and stillbirths).
The name "Turner syndrome" comes from Dr. Henry Turner, who first described the collection of findings in 1938. It was not until 1959 that the cause of Turner syndrome (having only a single X chromosome) was identified.
What Causes Turner Syndrome?
Males inherit the X chromosome from their mothers and the Y chromosome from their fathers, thereby having XY chromosomes. Females have XX chromosomes by inheriting one X chromosome from each parent.
In females who have Turner syndrome, one copy of the X chromosome is missing, partially missing or structurally altered.
The missing genetic material affects development before and after birth.
The genetic alterations of Turner syndrome may be one of the following:
Monosomy. The complete absence of an X chromosome generally occurs because of an error in the father's sperm or in the mother's egg. This results in every cell in the body having only one X chromosome. About half of individuals with Turner syndrome have this type of genetic alteration, also known as monosomy X.
Mosaicism. In some cases, an error occurs in cell division during early stages of foetal development. This results in some cells in the body having two complete copies of the X chromosome. Other cells have only one copy of the X chromosome. Females with Turner syndrome caused by X chromosome mosaicism are said to have mosaic Turner syndrome.
X chromosome abnormalities. Abnormal or missing parts of one of the X chromosomes can occur. Cells have one complete and one altered copy. This error can occur in the sperm or egg with all cells having one complete and one altered copy. Or the error can occur in cell division in early foetal development so that only some cells contain the abnormal or missing parts of one of the X chromosomes (mosaicism).
Y chromosome material. In a small percentage of Turner syndrome cases, some cells have one copy of the X chromosome and other cells have one copy of the X chromosome and some Y chromosome material. These individuals develop biologically as female, but the presence of Y chromosome material increases the risk of developing a type of cancer called gonadoblastoma.
Most cases of Turner syndrome are not inherited except in rare cases where Turner syndrome caused by a partial deletion of the X chromosome can be passed from one generation to the next. No environmental risks are known, and the mother's age does not play a role.
Signs and Symptoms
Turner syndrome can cause a variety of medical and developmental problems, including short stature, which is the most common feature, and this becomes evident by about age 5, failure of the ovaries to develop and heart defects, among others. Many affected girls do not undergo puberty unless they receive hormone therapy, and most are unable to conceive without fertility treatment. A small percentage of females with Turner syndrome retain normal ovarian function through young adulthood.
Signs and symptoms of Turner syndrome can be subtle, developing slowly over time, or significant and may vary among females with the disorder. For some females, the presence of Turner syndrome may not be readily apparent, but in others, a number of physical features and poor growth are apparent early.
Other signs and symptoms include:
Abnormal kidneys can also be found prenatally
A particularly short, wide neck with extra folds of skin, sometimes described as "web-like" (webbed neck) after birth
Broad chest with widely spaced nipples
High, narrow roof of the mouth (palate)
Arms that turn outward at the elbows
Fingernails and toenails that are narrow and turned upward
Swelling of the hands and feet, especially at birth
Low hairline at the back of the head
Receding or small lower jaw
Short fingers and toes
Early end to menstrual cycles not due to pregnancy
High waist-to-hip ratio (the hips are not much bigger than the waist)
Increased weight, obesity
Of the above common symptoms of Turner syndrome, an individual may have any combination of symptoms and is unlikely to have all symptoms. Turner syndrome manifests itself differently in each female affected by the condition; therefore, no two individuals share the same features.
Most girls and women with Turner syndrome have normal intelligence. Developmental delays, nonverbal learning disabilities, and behavioural problems are possible, although these characteristics vary among affected individuals.
Sometimes it's difficult to distinguish the signs and symptoms of Turner syndrome from other disorders. It's important to get a prompt, accurate diagnosis and appropriate care. See your doctor if you have concerns about physical or sexual development.
Turner syndrome can affect the proper development of several body systems, but varies greatly among females with the syndrome. Complications that can occur include:
High blood pressure.
Ear infections and hearing loss.
Autoimmune disorders, leading to an increased risk of an underactive thyroid, diabetes, celiac disease or inflammatory bowel disease.
Learning disabilities. Girls and women with Turner syndrome usually have normal intelligence. However, there is increased risk of learning disabilities, particularly with learning that involves spatial concepts, math, memory and attention.
Mental health issues. Girls and women with Turner syndrome may have difficulties functioning well in social situations and have an increased risk of attention-deficit/hyperactivity disorder (ADHD).
Turner syndrome may be diagnosed prenatally using prenatal cell-free DNA screening or prenatal ultrasound. Also, it can be diagnosed during infancy or in early childhood. Occasionally, in females with mild signs and symptoms of Turner syndrome, the diagnosis is delayed until the teen or young adult years.
No cure for Turner syndrome is known. However, much can be done to minimize the symptoms.
Treatment may help with symptoms, such as human growth hormone injections during childhood may increase adult height. Also, estrogen replacement therapy can promote development of the breasts and hips. Modern reproductive technologies have also been used to help women with Turner syndrome become pregnant if they desire. Cardiac surgery may be necessary to correct specific heart defects.
Some females with Turner syndrome may develop psychological problems, such as low self-esteem or depression. Psychological therapy, such as counseling or cognitive behavioural therapy (CBT), may be recommended.
Medical care is often required to manage other health problems with which Turner syndrome is associated. Females with Turner syndrome need ongoing medical care from a variety of specialists. Regular checkups and appropriate care can help most girls and women lead healthy, independent lives.
....making effort to "STAY WELL"