Turner Syndrome: Hormonal Aspects

Turner syndrome is a genetic condition that affects girls and women, in which one of the two X chromosomes is missing or partly missing. It commonly affects growth and the function of the ovaries, so hormones play a central role in both its signs and its care. Diagnosis involves a genetic test alongside hormone and other evaluations.

What Turner syndrome is

People typically have two sex chromosomes. In Turner syndrome, a girl has only one fully working X chromosome instead of two, either because the second is entirely absent or because it is partly missing or altered. This change is present from before birth and affects how certain parts of the body, including the ovaries, develop. The condition varies a great deal from person to person.

Two features stand out from a hormonal point of view. First, growth is often affected, so height tends to be shorter than expected without treatment. Second, the ovaries frequently do not develop or function fully, which influences puberty and the production of female sex hormones such as oestrogen. Understanding these endocrine aspects helps explain much of how the condition is recognised and managed.

Common signs and symptoms

Features differ widely, and some are present at birth while others become apparent during childhood or adolescence. They may include:

• Slower growth and shorter height than peers
• Puberty that does not begin or does not progress as expected
• Absent or irregular menstrual periods
• Physical features that a clinician may notice, which vary from person to person
• Associated health considerations, such as effects on the heart, kidneys, hearing, or thyroid, that prompt monitoring

What causes it

Turner syndrome is caused by the loss of all or part of one X chromosome. This usually happens by chance around the time of conception and is generally not inherited from a parent, so it is not typically the result of anything a parent did or did not do. In some people every cell is affected, while in others only some cells carry the chromosome change, a pattern called mosaicism, which can influence how the condition appears.

How it is diagnosed

Diagnosis may occur before birth, in childhood when growth or puberty raises a question, or sometimes later. Common steps include:

• Genetic test (karyotype) — a blood test that examines the chromosomes is the test that confirms the diagnosis.
• Hormone blood tests — measuring the pituitary signalling hormones and oestrogen helps show how the ovaries are functioning.
• Thyroid tests — thyroid function is often checked because related conditions can occur.
• Imaging and other evaluations — assessments of the heart, kidneys, and hearing are commonly arranged as part of overall care.

For background on the relevant tests, see our blood tests and hormones sections, our life stages overview, and the related page on Klinefelter syndrome.

How it is generally managed

Care is coordinated by a team and tailored to the individual across childhood and adulthood. From a hormonal standpoint, two areas are common. Growth is often supported with growth hormone treatment during childhood, guided by a specialist. When the ovaries do not produce enough oestrogen, hormone treatment may be used to help puberty progress and to support bone and general health, again under specialist guidance. Regular monitoring of the heart, thyroid, hearing, and other areas is an important part of long-term care. General treatment principles are outlined in our treatments section. This page is educational and is not a substitute for personalised medical advice.