SMAD4 and Restrictive ventilatory defect: Myhre syndrome is a skeletal dysplasia characterized by short stature, brachydactyly, and joint stiffness, with laryngotracheal stenosis and restrictive respiratory insufficiency leading to increased mortality as the result of Smad4 dysregulation (Caputo et al., 2012; Le Goff et al., 2012, 2014; Caputo et al., 2014).