Long-Term Evaluation of Mandibular Growth in Children With FGFR2 Mutations

Background: Understanding mandibular growth in children with fibroblast growth factor receptor 2 (FGFR2) mutations is important for planning the degree of midface advancement, and for determining the best treatment for obstructive sleep apnea. Yet, relatively little is known about growth of the unoperated mandible in affected children. The purpose of this study was to evaluate mandibular growth through skeletal maturity in Apert, Crouzon, and Pfeiffer syndromes. Methods: A retrospective chart review was performed. Long-term, unoperated mandibular growth was assessed using multiple anthropologic measurements including: mandibular width, height, depth, and the cranial base width (approximating bicondylar width). Measurements were compared over 3 age intervals: 6 to 7 years, 10 years, and at skeletal maturity (15 years+). Results: Out of 327 treated patients with FGFR2 mutations, 21 were found to have complete mandibular measurements through skeletal maturity (11 Apert, 7 Crouzon, and 3 Pfeiffer). Initial measurements revealed that mandibular height and bigonial breadth were slightly larger than normal, but sagittal depth and cranial base width were deficient. Early growth was slightly accelerated along the vertical and sagittal axes, stable across the bigonial distance, and marked deficient at the cranial base. At skeletal maturity, vertical height and bigonial width remained above average, but mandibular depth (forward sagittal growth) and cranial base width, remained deficient. Conclusions: Mandibular growth in children with FGFR2 mutations is not normal with impairments found in forward sagittal growth and skull base widening. Knowledge of these deficiencies has significant implications for both planning the degree of midfacial advancements, as well as treating obstructive sleep apnea.