[Nosologic evaluation of Noonan syndrome and description of nine cases]

Noonan syndrome was first described over 20 years ago by Noonan and Ehmke. They defined a specific group of nine patients with valvular pulmonary stenosis who, in addition, had short stature, mild mental retardation, hypertelorism and unusual facies. The incidence of Noonan syndrome has been estimated to be between 1 in 1000 and 1 in 2500 live births. The primary biochemical defect in Noonan's syndrome is unknown. We analyzed 9 patients (5 males and 4 females) in an age range of 6 months to 10 years and 3 months with Noonan syndrome. Patients were diagnosed as having the syndrome if they had characteristic facies and a normal karyotype, plus one of the following signs: cardiac defects, short stature or undescended testes. All patients have ocular anomalies (epicanthal folds, ptosis of eyelids, hypertelorism, downslanting palpebral fissures and ocular proptosis). Congenital heart malformations are present in 8 patients and the more frequent cardiopath is pulmonary valve stenosis due to a dysplastic or thickened valve. Short stature is present in 6 patients and 3 of them are actually on treatment with rhGH. A moderate-mild mental retardation is present in 6 patients. Case n. 9 had a syringomyelia and tethered cord. These malformations are rarely reported in Noonan's syndrome.