Severe trismus due to bilateral elongated mandibular coronoid process in an infantile-onset Pompe disease patient: A case report

Pompe disease is a rare neuromuscular disorder characterized by orofacial muscle weakness with consequent dysphagia and poor weight gain. We report the first case of severe trismus due to abnormal elongation of the coronoid process of the mandible in a child with infantile-onset Pompe disease. Bilaterally elongated mandibular coronoid processes cause abnormal impingement between the coronoid process and the zygomatic process, which in this patient, resulted in a maximal interincisal opening of only 6 mm. Although rare, clinicians should be aware of the development of coronoid process elongation in neuromuscular disorders with hypotonia, specifically those involving hypotonic orofacial muscles.