Noonan syndrome: a clinical and genetic study of 31 patients. D. Bertola1, C.A. Kim1, S.M.M. Sugayama1, L.M.J. Albano1, J.D.A. Carneiro1,2, E.A. D'Amico2, C.H. Gonzalez1. 1) Dept. of Pediatrics, Instituto da Crianca, University of Sao Paulo, Sao Paulo, Brazil; 2) Dept. of Hematology, Hospital das Clinicas, University of Sao Paulo, Sao Paulo, Brazil.
Noonan syndrome is an autosomal dominant disorder comprising short stature, facial dysmorphisms, webbed neck, heart defect, cryptorchidism in the males, skeletal defects and abnormal hematological indices. In the present study, 31 affected patients, belonging to 26 families, were studied regarding their clinical and genetic characteristics. The isolated and familial propositus were separately analyzed from the affected relatives. Short stature was present in 69% of the propositus. The most common craniofacial dysmorphisms were ocular hypertelorism (62%), ptosis (58%) and downslanting of the palpebral fissures (42%), as well as high-arched palate and dental malocclusion. A webbed neck occurred in 42% of the propositus. The most frequent cardiac lesions, presented in 73% of the cases, were pulmonary valvar stenosis and hypertrophic cardiomyopathy. The eletrocardiogram frequently showed a superior QRS axis deviation. The abdominal ultrasound indicated the presence of hepatomegaly, splenomegaly or renal anomalies in less than 10% of the cases. Cryptorchidism occurred in 50% of the male propositus. The most common limb anomalies were prominent fetal pads on the fingers and toes and short and wide nails. The sternal deformity occurred in 54% of the propositus and the vertebral anomalies were observed in 23%. Abnormal hematological indices were present in 31% of our propositus, especially factor XI deficiency. The relatives showed less signs of the condition when compared to the propositus. In the 24 families in which the propositus' parents and sibs were evaluated, three (12.5%) had more than one affected, and so were considered familial cases. Therefore, the majority of the cases were sporadic.