AKT · Child health/Genetic syndromes

Turner syndrome

45,X monosomy (female)

Overview

Loss of one X chromosome (45,X) in phenotypic females, causing short stature, ovarian dysgenesis (primary amenorrhoea/infertility) and characteristic features. The classic cardiac lesion is coarctation/bicuspid aortic valve.

Recognise

SHORT STATURE; webbed neck; widely spaced nipples, broad "shield" chest
Cubitus valgus; low posterior hairline; lymphoedema of hands/feet in neonate
Primary amenorrhoea, streak ovaries, infertility; normal intelligence

Red flags

Coarctation of the aorta / bicuspid aortic valve; aortic dissection risk; renal anomalies

Differentials & how to tell them apart

Noonan syndromesimilar webbing/short stature but NORMAL karyotype, affects both sexes, pulmonary stenosis (not coarctation)

Constitutional short staturenormal karyotype, no dysmorphism/ovarian failure

GH deficiencynormal karyotype

Investigations

Karyotype 45,X (or mosaicism). Echo/MRI aorta, renal USS, TFTs, FSH/LH (raised — hypergonadotropic hypogonadism).

Management

1Confirm karyotype. Growth hormone for stature; oestrogen for pubertal induction and maintenance.
2Cardiac (coarctation/bicuspid valve, aortic dilation) and renal surveillance; fertility counselling.

Growth hormone — for short stature

Oestrogen replacement — induce puberty; then maintenance

Key points

Turner = coarctation/bicuspid valve; Noonan (the "male Turner", normal karyotype) = pulmonary stenosis. That cardiac pairing is high-yield.

Monitor & prognosis

Aorta (dilation/dissection), cardiac, renal, thyroid, growth, bone health.

Good with hormone therapy; cardiovascular surveillance important.

Source: Clinical genetics; NICE