Keywords: Noonan syndrome, conductive hearing loss

Abstract: The authors report a 17 years old young woman with NGONAN'S SYNDROME, in whom hypoacusis of transmission isolated was discovered. At surgery of the middle ear, ore side presented an atical fixation of the ossicles chain, and, the other side, the articulation incus-stapes was unfixed. They remark the negligence with the hearing test in these patients, in whom the verbal expression and the intellectual level are involved. Finaliy, they study the deafness, the etiopathogenesis, and the possibility of anomaly of development in this syndrome.