Associations

Noonan's syndrome is associated with right-sided heart defects - in particular pulmonary artery stenosis, but also tetralogy of Fallot. By comparison Turner's syndrome is associated with left-sided heart defects.

There may be hypertrophic cardiomyopathy.

Mental retardation may occur in this condition, but is by no means a mandatory feature.

Reference

1. Jorge AA, Malaquias AC, Arnhold IJ, et al. Noonan syndrome and related disorders: a review of clinical features and mutations in genes of the RAS/MAPK pathway. Horm Res. 2009;71(4):185-93.