Turner syndrome is caused by the deletion of part or all of one of the two X chromosomes.
Girls with the syndrome are typically short and with 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.
Chromosomes Chromosomes Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are structures within cells... read more are structures within cells that contain DNA DNA Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are structures within cells... read more and many genes. A gene is a segment of deoxyribonucleic acid (DNA) and contains the code for a specific protein that functions in one or more types of cells in the body (see Genes and Chromosomes Genes and Chromosomes Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are structures within cells... read more for a discussion about genetics). Genes contain instructions that determine how the body is supposed to function.
The sex chromosomes Sex chromosomes Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are structures within cells... read more determine whether a fetus becomes male or female. A pair of X and Y chromosomes (XY) results in a male, and a pair of X and X chromosomes (XX) results in a female.
Turner syndrome occurs in about 1 out of 2,500 live female births. However, this chromosome abnormality is much more common at conception, but 99% of affected fetuses abort spontaneously.
Some symptoms of Turner syndrome are noticeable at birth. Other symptoms are not noticed until the children are school-age or older.
Many newborns with Turner syndrome are mildly affected, but some have swelling (lymphedema Lymphedema Lymphedema is the accumulation of lymph in tissues, resulting in swelling. When lymphatic vessels are injured or obstructed, lymph fluid cannot drain and accumulates in tissues, causing swelling... read more ) 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. Heart defects include narrowing of part of the aorta (coarctation of the aorta Coarctation of the Aorta Coarctation of the aorta is a narrowing of part of the aorta, the main blood vessel bringing red oxygenated blood from the heart to the body. The aorta narrows, causing the heart to pump harder... read more ). Other abnormalities seen later include a webbed neck (wide skin attachment between the neck and shoulders) and a broad chest with widely spaced and inwardly turned nipples. Infants are at a higher risk of a problem with the hip joint called developmental dysplasia of the hip Developmental Dysplasia of the Hip Developmental dysplasia of the hip is a birth defect in which the bones in the hip may be incorrectly developed. In developmental dysplasia of the hip, formerly called congenital dislocation... read more . Less common symptoms include drooping upper eyelids (ptosis), a low hairline at the back of the neck, moles Moles Moles are small, usually dark, skin growths that develop from pigment-producing cells in the skin (melanocytes). Most people have some moles, but the tendency to develop atypical moles is sometimes... read more (nevi), and poorly developed nails.
Girls with Turner syndrome generally do not have menstrual periods (amenorrhea Absence of Menstrual Periods Having no menstrual periods is called amenorrhea. Amenorrhea is normal in the following circumstances: Before puberty During pregnancy While breastfeeding read more ), and the breasts, vagina, uterus, and labia remain childlike rather than undergoing the changes of puberty (delayed puberty Delayed Puberty Delayed puberty is defined as absence of the start of sexual maturation at the expected time. Most often, children simply develop later than their peers but ultimately develop normally. Sometimes... read more ). About 10% of adolescents have scoliosis Scoliosis Scoliosis is abnormal curvature of the spine. Scoliosis can be present at birth or can develop during adolescence. Mild forms may cause only mild discomfort, but more severe forms can cause... read more . In 90% of girls, the ovaries are replaced by connective tissue and do not contain developing eggs (gonadal dysgenesis), so these girls are infertile. A girl or woman with Turner syndrome is often short compared with family members, and obesity is common.
Other disorders may develop. High blood pressure High Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more frequently occurs with aging even if the girl does not have coarctation. Kidney defects, diabetes mellitus Diabetes Mellitus (DM) in Children and Adolescents Diabetes mellitus is a disorder in which blood sugar (glucose) levels are abnormally high because the body does not produce enough insulin or fails to respond normally to the insulin produced... read more , and thyroid diseases are common. Occasionally, abnormal blood vessels in the intestine cause bleeding. Hearing loss Hearing Impairment in Children Hearing loss in newborns most commonly results from cytomegalovirus infection or genetic defects and in older children results from ear infections or earwax. If children do not respond to sounds... read more occurs, and crossed eyes (strabismus Strabismus Strabismus is an intermittent or constant misalignment of an eye so that its line of vision is not pointed at the same object as the other eye. If untreated, strabismus can cause amblyopia ... read more ) and farsightedness (hyperopia) are common. Celiac disease Celiac Disease Celiac disease is a hereditary intolerance to gluten (a protein found in wheat, barley, and rye) that causes characteristic changes in the lining of the small intestine, resulting in malabsorption... read more , inflammation of the thyroid gland, and diabetes mellitus occur more frequently among girls with Turner syndrome than among the general population. There is an increased risk of an enlarged aorta so girls need to be screened regularly with echocardiography.
Many girls with Turner syndrome have attention-deficit/hyperactivity disorder Attention-Deficit/Hyperactivity Disorder (ADHD) Attention-deficit/hyperactivity disorder (ADHD) is poor or short attention span and/or excessive activity and impulsiveness inappropriate for the child’s age that interferes with functioning... read more and learning disabilities Learning Disorders Learning disorders involve an inability to acquire, retain, or broadly use specific skills or information, resulting from deficiencies in attention, memory, or reasoning and affecting academic... read more 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. Intellectual disability is rare.
Doctors may suspect the diagnosis of Turner syndrome if a newborn has lymphedema or a webbed neck. However, they may not suspect the syndrome until adolescence, when the girl is short and has delayed puberty Delayed Puberty Delayed puberty is defined as absence of the start of sexual maturation at the expected time. Most often, children simply develop later than their peers but ultimately develop normally. Sometimes... read more .
To confirm the diagnosis, the chromosomes are analyzed using a blood test.
Doctors do echocardiography Echocardiography and Other Ultrasound Procedures Ultrasonography uses high-frequency (ultrasound) waves bounced off internal structures to produce a moving image. It uses no x-rays. Ultrasonography of the heart (echocardiography) is one of... read more or magnetic resonance imaging Magnetic Resonance Imaging (MRI) of the Heart With magnetic resonance imaging (MRI), a powerful magnetic field and radio waves are used to produce detailed images of the heart and chest. This expensive and sophisticated procedure is used... read more (MRI) of the heart to detect heart problems.
There is no cure for Turner syndrome. However, some specific symptoms and problems caused by the syndrome can be treated. Coarctation of the aorta is usually repaired surgically. Doctors monitor and repair other heart defects as needed. Lymphedema can usually be controlled with support hosiery and other techniques such as massage.
Treatment with growth hormone can stimulate growth. Once satisfactory growth has been achieved, treatment with growth hormone is stopped.
Treatment with the female hormone estrogen is usually needed to initiate puberty Puberty in Girls Puberty is a sequence of events in which physical changes occur, resulting in adult physical characteristics and capacity to reproduce. These physical changes are regulated by changes in the... read more and is typically given at age 12 to 13 but is usually not started until after satisfactory growth has been achieved. After girls have undergone puberty, they are given birth control pills that contain estrogen plus another female hormone, progestin. This hormone treatment helps girls maintain their female sexual characteristics. Estrogen treatment may also improve the girl’s ability to plan tasks, pay attention, and assess visual and spatial relationships and also helps the bones become dense and helps the skeleton develop properly.
Some girls who have Turner syndrome begin puberty normally without estrogen replacement therapy, but this is more common among girls who are mosaic. Girls who have mosaic Turner syndrome have a mixture of two or more types of cells. Some of their cells contain two X chromosomes and some cells contain just one X chromosome. Such girls may become pregnant but they usually require fertility treatments Assisted Reproductive Techniques Assisted reproductive techniques involve manipulating sperm and eggs or embryos in a laboratory (in vitro) with the goal of producing a pregnancy. (See also Overview of Infertility.) If treatment... read more .
Girls with Turner syndrome should have regular evaluations to detect problems that may result from this disorder. Evaluations include the following: