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.