What is Genetic Testing for Turner syndrome?

Genetic testing for Turner syndrome

What is Turner syndrome?

Turner syndrome is a rare disease known only to affect females. The exact prevalence of the syndrome is unknown, but it is believed to occur in every 1 in every 2,000 females born. Symptoms of the syndrome include a short stature, congenital heart defects, and a failure of the reproductive issues to develop. 

Due to the nature and type of its syndrome, it is not often diagnosed until puberty when the main symptoms of the syndrome become more noticeable. However testing exists to diagnose the syndrome both before and after birth. 

Genetic testing for Turner syndrome

There are several ways to test for Turner syndrome, both prenatally and after birth. The syndrome is not inherited, and is always the result of a random or new chromosomal anomaly. Girls born with Turner syndrome have only one normal X chromosome, the second X chromosome is partially or completely missing. 

Because the syndrome is not inherited, carrier screening is not relevant, as it is not a chromosomal change either parent can carry.

Prenatal genetic testing for Turner syndrome

There are several ways to identify Turner syndrome, or suspected Turner syndrome in an unborn child. Sometimes a routine ultrasound, or a fetal anomaly ultrasound, may reveal physical signs of Turner syndrome. This identification is not enough in itself to warrant a confirmed diagnosis, but it could lead to a strong recommendation for more advanced and targeted genetic screening, to rule out or confirm the syndrome. 

Other types of prenatal screening may identify higher risk for Turner syndrome in a baby- including NIPT (non-invasive prenatal screening or cell-free DNA testing), but this would need to be followed by karyotype genetic testing to confirm an actual diagnosis. 

If screening identifies higher risk for Turner syndrome prenatally, a doctor or genetic counselor might recommend more targeted, and accurate genetic testing for the syndrome. 

This testing might take the form of Chorionic villus sampling (CVS) or Amniocentesis. Both are invasive forms of testing that require taking samples from either the placenta or amniotic fluid surrounding the growing baby. Both forms of genetic testing have a high rate of accuracy for diagnosing Turner syndrome. 

Postnatal genetic testing for Turner syndrome

Turner syndrome may be diagnosed in a child, teenager or even adult through karyotype testing. This involves taking a sample of blood and identifying the chromosomal anomaly which causes Turner syndrome. This form of testing is highly accurate, with an accuracy rate of 99.9%

Genetic testing for Turner syndrome may be recommended if a girl is showing symptoms of Turner syndrome. These are often noticed first during puberty. 

Genetic counseling

Genetic counseling is essential for anyone facing a diagnosis of Turner syndrome. This is because genetic counseling can help understand possible symptoms of the syndrome and the types of genetic testing necessary for an accurate diagnosis. It can help reduced Turner syndrome misdiagnosis rates. 

Genetic counseling for Turner syndrome can also help patients with emotional support and counseling, and help them connect to other patients and families with the same diagnosis. 

Genetic counseling is an important support service for rare disease patients, including Turner syndrome patients.  

 

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