Patients With Mucopolysaccharidosis Have Tendencies Towards Vertical Facial Growth

PurposeStudies addressing the changes in craniofacial morphology of patients with mucopolysaccharidosis (MPS) are important for a better understanding of the progression of this disease. The present objective was to identify major cephalometric abnormalities in these patients.Materials and MethodsThis was a cross-sectional case-and-control study. The sample was composed of 2 types of study subjects (patients with MPS and normal subjects). The outcome variables were numerous cephalometric elements that measure facial height, dental positioning, facial growth pattern, and mandibular and maxillary positioning. The Student t test was used to compare the mean angular and linear measurements of the case and control groups and the level of significance was set at a P value less than .05. The Bonferroni method was used for adjustment of the P value (P < .003 was deemed significant).ResultsThe control group consisted of randomly selected subjects matched to the patients with MPS for the demographic variables of gender and age. Seventeen patients with MPS were evaluated (64.7% female). The mean age of the sample was 13.29 years. One patient had MPS I, 8 had MPS IV, and 8 had MPS VI. The results showed important differences between groups in angular measurements (angle formed by the line between the sella and nasion [SN] and the plane of the gonion and gnathion, angle formed by the intersection of the gnathion point and the SN line, angle formed by the intersection of the long axis of the lower incisor with the line between the nasion and the B point, angle formed by the intersection of the long axes of the upper and lower incisors, and angle formed by the Frankfort horizontal plane with the mandibular plane) and linear measurements (condyle to A point, condyle to gnathion, pro-nasal ( Pn) point to the line between the pogonion and upper incisor, and the nearest point of the anterior half of the soft palate to the posterior pharyngeal wall). The angle formed by the SN line with the plane between the gonion and the gnathion and the distance from the condyle to the A point showed meaningful differences after Bonferroni adjustment.ConclusionPatients with MPS present a tendency toward vertical growth that results in a dolichocephalic facial pattern. In addition, a smaller nasopharyngeal space was observed, a factor that might be responsible for the mouth breathing observed in these patients.