IRAK 1 variant is protective for orthodontic‐induced external apical root resorption

Objective Interleukin‐1 beta ( IL 1B) pathway is a key player in orthodontic‐induced external apical root resorption ( EARR ). The aim of this work was to identify the genes related to the IL 1 pathway as possible candidate genes for EARR , which might be included in an integrative predictive model of this complex phenotype. Materials and Methods Using a stepwise multiple linear regression model, 195 patients who had undergone orthodontic treatment were assessed for clinical and genetic factors associated with % EARR max (maximum % EARR value obtained for each patient). The four maxillary incisors and the two maxillary canines were assessed. Three functional single nucleotide polymorphisms ( SNP s) were genotyped: rs1143634 in IL 1B gene, rs315952 in IL 1 RN gene, and rs1059703 in X‐linked IRAK 1 gene. Results The model showed that four of the nine clinical variables and one SNP explained 30% of the % EARR max variability. The most significant unique contributions to the model were gender ( P  =   0.001), treatment duration ( P  < 0.001), premolar extractions ( P  =   0.003), Hyrax appliance ( P  <   0.001), and homozygosity/hemizygosity for variant C from IRAK 1 gene ( P  =   0.018), which proved to be a protective factor. Conclusion IRAK 1 polymorphism is proposed as a protective variant for EARR .