Pycnodysostosis (PDO) is a rare genetic disorder characterized by cathepsin K deficiency which plays an important role in bone metabolism. Among clinical features of this disease which are mainly caused by altered bone remodeling are craniofacial abnormalities such as hypoplastic maxilla and obtuse gonial angle which consequently lead to respiratory insufficiency in forms of pharyngeal narrowing and severe snoring. In this paper, another case of this rare disorder is presented along with a review on etiology and management issues of respiratory insufficiency in these patients.