Interleukin-1 Polymorphisms in Relation to External Apical Root Resorption (EARR)

Aim: Recent papers have discussed genetic predisposition for root resorption. The aim of this study was to investigate this kind of relationship as dependent on the EARR phenotype. Alleles from IL-1A and IL-1B gene polymorphisms are discussed as genetically predisposing factors. Material and Methods: Orthopantomograms (OPG) exhibiting EARR (n = 96) were metrically and statistically analyzed for expression and were compared to a control group (n = 162). Additionally, the percentage of affected teeth per individual was determined. A subgroup of the EARR patient sample (n = 49) was assessed, based on blood analyses, for an association with genomic IL-1A (-889) and IL-1B (+3954) polymorphism. Results: In the case of the IL-1A variation, a significant difference of genotype distribution was found between EARR patients and the control group: genotype 2-2 could be seen significantly more frequently in the EARR group. Furthermore, the extent of resorption grades seemed to be influenced by the genetic constitution. The genotype distribution of the IL-1B polymorphism was comparable to the distribution in the control sample. In particular, allele 1 of the IL-1B polymorphism, which has been described as being associated with family histories of EARR, was observed less frequently in the patient cohort than in the control group. Conclusions: The available data of the IL-1A polymorphism point to an association of the genotype 2-2 with EARR. As analyses of individual subgroups showed, with the increase in the extent of EARR there was a recognizable correlation with genotype 2-2. The genotype distribution of the IL-1B polymorphism in patients and control cohorts revealed no indication of a predisposition. Despite the low number of cases in the own cohort, the data collected revealed that the allele 1 of the IL-1B polymorphism in patients with sporadic EARR did not contribute to predisposition, in contrast to familial cases. The results are an initial basis for pre-orthodontic genetic EARR risk analyses.