It is not always easy to diagnose Turner syndrome at an early stage.

However, it is sometimes mentioned in the prenatal period on ultrasound abnormalities. A sample of amniotic fluid can then allow a definite diagnosis. Turner syndrome can also be detected on a birth exam. But most often, it is discovered in adolescence.

The diagnosis is made using a karyotype, which is an analysis of the chromosomes and which detects the abnormalities present.