Abnormal mandibular growth after craniovertebral surgery in Morquio syndrome type A

Morquio syndrome or MPS4A is an autosomal recessive inherited metabolic disease, due to a deficiency of N-acetil-galactosamine-6-sulfatase (OMIM 253000). Hypoplastic odontoid processes causing atlantoaxial subluxation and cervical myelopathy are usual clinical findings. Surgical intervention of craniocervical fusion is often performed to prevent this complication. Clinical and cephalometric findings in a patient affected by Morquio syndrome after craniovertebral surgery are described. Facial growth pattern in the lateral plane changed dramatically. The mandibular gonial angle (ArGoMe), the body of the mandible (GoGn), and the total length of the mandible (CoGn) increased abnormally, whereas the mandibular ramus (CoGo) exhibited normal growth. Knowledge of the possibility of abnormal mandibular growth may contribute in long-term orthodontic management of such subjects.