Non-clinical sciences/Genetics · Chromosomal

Turner & Klinefelter syndromes

What it means

Turner (45,X): short stature, webbed neck, widely spaced nipples, primary amenorrhoea/ovarian dysgenesis, bicuspid aortic valve & coarctation, normal intelligence. Klinefelter (47,XXY): tall, small firm testes, infertility, gynaecomastia, reduced secondary sexual hair, mild learning difficulty; low testosterone, high LH/FSH.

Worked example

Short girl with primary amenorrhoea, webbed neck and coarctation → Turner (karyotype confirms 45,X).

In the exam

A short adolescent girl has a webbed neck, primary amenorrhoea, and a bicuspid aortic valve with coarctation.

What settles it

Turner = 45,X (short, female, gonadal dysgenesis); Klinefelter = 47,XXY (tall, male, hypogonadism).

Classically confused with

Down syndrome (trisomy 21)

Source: StatPearls