Turner syndrome (TS) is a hereditary disorder affecting young girls and women, caused by a missing, partially missing, or modified X chromosome
Turner syndrome (TS) is a hereditary disorder affecting young girls and women, caused by a missing or partially missing X chromosome.
Each cell in the human body has two sex chromosomes. Women have two X chromosomes and men have one X chromosome and one Y chromosome.
In girls with Turner syndrome, one of the X chromosomes is missing, partially missing, or modified. This defect results in problems during fetal development and other developmental problems after birth.
The genetic alterations of Turner syndrome may be one of the following:
- Monosomy: Absence of the X chromosome that occurs due to a defect in the father’s sperm or in the mother's egg.
- Mosaicism: An error may occur in cell division during the early phases of a fetus’ development. This causes a few cells in the body to have two complete X chromosomes, and the other cells to have just one copy.
- X chromosome abnormalities: If abnormal or missing pieces of one of the X chromosomes occurs, all cells have one complete and one altered copy of the X chromosome.
- Y chromosome material: In some cases, a few cells have one copy of the X chromosome while other cells have a copy of the X chromosome as well as some Y chromosome material.
What are the signs and symptoms of Turner syndrome?
The main symptom of Turner syndrome is short stature. All females with TS grow more slowly than others during youth and adolescence, have delayed puberty, and experience no growth spurts.
Another key symptom is irregular sexual development. Most females with TS present with the following:
- Absence of normal breast development
- Might not have menstrual periods
- Have small ovaries that may function for only a few years or not at all
- Normally do not go through puberty
- Do not make sex hormones
Females with Turner syndrome regularly have other physical characteristics such as:
- Broad chest
- Cubitus valgus (a deformity where the forearm is angled away from the torso when the arm is fully extended)
- Dental issues
- Eye issues (drooping eyelids, etc.)
- Scoliosis (spine bends sideways)
How is Turner syndrome diagnosed?
After considering the symptoms, a blood test is done to analyze the child’s chromosomes. In some cases, a buccal smear or skin sample may also be ordered. The chromosome analysis determines whether there is a missing X chromosome or abnormality in any one of the X chromosomes.
In some cases, a diagnosis is made during fetal development. Prenatal screening tests are conducted to help assess the child's DNA in the mother's blood (prenatal cell-free DNA screening or noninvasive prenatal screening), which may help identify the risk of Turner syndrome.
What is the treatment for Turner syndrome?
There is no cure for Turner syndrome. However, therapies have been developed that can help improve physical development. Because symptoms and causes vary, treatments are customized to resolve problems particular to each patient.
Typical treatments involve growth hormone treatment and estrogen treatments:
- Growth hormone (GH) therapies can help normalize height. Usually, the earlier GH treatment is begun, the more effective it is.
- Sex hormone replacement therapy may help the affected person attain physical development related to adolescence. Estrogen and progesterone replacement treatment may help advance puberty, lead to the improvement secondary sexual attributes, and cause the affected person to start menstruating.
Other treatments are symptomatic and supportive.