Turner syndrome is a genetic condition that only affects females. It is caused by an abnormal sex chromosome and affects about 1 in every 2,000 baby girls.

Sex chromosomes

Babies are usually born with 23 pairs of chromosomes. One pair of chromosomes determines the baby's sex. This pair are known as the sex chromosomes.

One sex chromosome comes from the father and the other one comes from the mother. The mother’s contribution is always an X chromosome. The father’s contribution can either be an X or a Y chromosome.

A baby girl usually has two X chromosomes (XX) and boys have an X and a Y chromosome (XY). The Y chromosome determines ‘maleness’, so if it is missing as in Turner syndrome, the sex of the child will invariably be female.

A female with Turner syndrome has part or all of one X chromosome missing. This means the girl has just one complete X chromosome rather than two.

Read more about the causes of Turner syndrome.

Characteristics of Turner syndrome

Females with Turner syndrome often have a wide range of symptoms and some distinctive characteristics. Two that occur in almost all cases of Turner syndrome are:

  • being shorter than average 
  • underdeveloped ovaries (female reproductive organs), resulting in a lack of monthly periods and infertility 

As height and sexual development are the two main characteristics, Turner syndrome is often undiagnosed until a girl reaches puberty (sexual maturity).

Other characteristics of Turner syndrome can vary significantly between individuals. For example, the syndrome can sometimes cause heart, kidney and thyroid problems, as well as bone disorders and ear problems.

Read more about the symptoms of Turner syndrome and how Turner syndrome is diagnosed.

Treating Turner syndrome

There is no cure for Turner syndrome, but many of the associated symptoms can be treated.

Girls and women with Turner syndrome will need to have regular health checks throughout their lives. However, it is usually possible to lead a relatively normal and healthy life.

Life expectancy is slightly reduced but it can be improved if regular health checks are maintained and any potential problems are identified and treated at an early stage.

Read more about treating Turner syndrome.

Turner syndrome is caused by a completely or partially missing X sex chromosome in females 

Types of Turner syndrome

Turner syndrome is named after Dr Henry Turner who first described it in 1938.

Depending on how much of a female's X chromosome is missing, the syndrome can either be described as:

  • classic Turner syndrome – where one of the X chromosomes is completely missing
  • mosaic Turner syndrome – where one X chromosome is complete in most cells, but the other is partially missing or abnormal in some way; in some cells, there may be just one X chromosome or, rarely, two complete X chromosomes

Teen girls 15-18

Read about teen girl health issues, including healthy eating, skin problems and having sex for the first time

Page last reviewed: 04/01/2013

Next review due: 04/01/2015