WNK2 and Pectus excavatum: Noonan syndrome (NS) is an autosomal dominant multisystem disorder caused by the dysregulation of the Rat Sarcoma/Mitogen-activated protein kinase (RAS/MAPK) pathway and characterized by short stature, heart defects, pectus excavatum, webbed neck, learning disabilities, cryptorchidism, and facial dysmorphia.