Clinical features are heterogeneous and typical physical anomalies are often mild or absent. Short stature is present in all cases. Ovarian failure, with variable onset depending on the chromosomal anomalies, is frequent. Other visceral manifestations (bone anomalies, lymphoedema, deafness, and cardiovascular, thyroid and gastrointestinal involvement) are less common but should be screened for at diagnosis, then monitored during adolescence and adulthood.
X-chromosome monosomy is responsible for less than half of the cases of Turner syndrome and a large majority of cases are caused by the presence of a mosaicism (45,X) and/or an abnormal X or Y chromosome (deletion, isochromosome X, dicentric chromosome).
