Obstructive sleep apnea syndrome (OSAS) in children with Class III malocclusion : involvement of the PHOX2B gene

PURPOSE: The aim of this study is to provide new molecular approaches to the children with obstructive sleep apnea syndrome by evaluating the possible involvement of the PHOX2B gene, notoriously associated to congenital central hypoventilation syndrome (CCHS), in Class III malocclusion. METHODS: Fifty subjects with Class III malocclusion, aged from 8 to 14 years, and with history of sleep apneic episodes, and 20 age-matched controls were submitted to genomic DNA examination from oral cells to specifically analyze the PHOX2B genotype. RESULTS: Point "silent" mutations affecting different nucleotides of the PHOX2B gene were observed in 32 % of patients with Class III malocclusion and never in controls (0 %). CONCLUSION: The genetic data obtained in this study in children with Class III malocclusion and sleep-related breathing disorders provide new information useful to the genetic characterization of this pathology. The PHOX2B gene silent mutations can lead to structural and functional modification of their product providing to a group of children with Class III malocclusion similar features to those of CCHS (sleep apnea episodes and craniofacial malformations).