Identification of a novel de novo deletion in RAF1 associated with biventricular hypertrophy in Noonan syndrome.

Biventricular hypertrophy (BVH) is a disease state characterized by the thickening of the ventricle walls. The differential diagnosis of BVH with other congenital and familial diseases in which increased ventricle wall thickness is a prominent clinical feature is fundamental due to its therapeutic and prognostic value, mainly during infancy. We describe a 2-month-old infant presenting BVH. Using exome sequencing, we identified a novel de novo 3-bp deletion in the RAF1 gene that is located in the binding active site for the 14-3-3 peptide. Based on docking calculations, we demonstrate that this novel mutation impairs protein/target binding, thus constitutively activating Ras signaling, which is a dysregulation associated with Noonan syndrome. Finally, our study underlines the importance of molecular modeling to understand the roles of novel mutations in pathogenesis.