Watson syndrome (WTSN) is an autosomal dominant disorder characterized by pulmonary stenosis, cafe-au-lait spots, reduced intellectual abilities (Watson, 1967) and short stature (Partington et al., 1985). Most affected individuals have relative macrocephaly and Lisch nodules and about one third of those affected have neurofibromas (see Neurofibromatosis Noonan syndrome below).