Turner syndrome occurs when a female has a single X chromosome, making them 45 XO. The O indicates an absence of the other X chromosome.
Mosaicism can occur, in which some cells of the body contain X0 sex chromosomes, while others contain the normal XX sex chromosomes. This typically results in milder symptoms.
Features
- Short stature
- Webbed neck
- Broad chest with widely spaced nipples
- High-arched palate
- Downward-sloping palpebral fissures (the gaps between the lower and upper eyelid)
- Prominent epicanthic folds (the folds of skin overlying the medial portion of the eye and eyelid)
- Low posterior hairline
- Cubitus valgus (exaggerated angle at the elbow, with the forearm angled away from the body)
- Short 4th metacarpal bone (resulting in a short 4th finger)
- Hypogonadism (underdeveloped ovaries)
- Late or incomplete puberty
- Infertility
TOM TIP: For exams, remember short stature, webbed neck and widely spaced nipples.
Associated Conditions
Turner syndrome is associated with an increased risk of various conditions:
- Recurrent otitis media
- Recurrent urinary tract infections secondary to congenital renal anomalies (e.g., horseshoe kidney)
- Aortic pathology (e.g., coarctation, bicuspid aortic valve, aortic root dilatation and aortic dissection)
- Hypothyroidism
- Metabolic syndrome, with hypertension, obesity and type 2 diabetes
- Osteoporosis
- Specific learning difficulties (e.g., with maths or visual-spatial skills)
Management
Treatment aims to help with the features of the condition:
- Growth hormone therapy to improve adult height
- Oestrogen and progesterone replacement
- Fertility treatment (e.g., with egg donation) may enable pregnancy, although pregnancy is considered high-risk
Prognosis
Life expectancy is close to normal, but may be reduced by associated conditions (e.g., aortic dissection).
Last updated December 2025
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