The EDAR V370A is Associated With the Teeth Root Shape

Objectives: A nonsynonymous polymorphism of EDAR (rs3827760), V370A in the amino acid position or T1540C in the nucleotide position, is attracting attention due to the presence of a trace of Asian-specific strong positive selection on the 370A allele. It is shown that the 370A allele is related to the Asian-specific phenotypes such as thick hair and shovel-shaped incisors. In this study, we investigated the relationship between the teeth root morphology and the EDAR variants.

Methods: We subjected 290 patients (110 males and 190 females) who visited the Department of Dental and Oral Surgery, University of the Ryukyus Hospital, and underwent a cone beam CT examination for treatment. Written informed consent was obtained from all the participants. Three-dimensional tooth root morphology was investigated from CT images of craniofacial area. SNP genotyping was performed by the TaqMan assay.

Results: It was found that the EDAR 370A allele was related to triple roots and C-shaped root of the mandibular first and second molars (LM1 and LM2), respectively. Since triple root of LM1 and C-shaped root of LM2 are more common in Asians than other groups, the Asian-specific 370A allele can also explain phenotypic differentiation between populations. No significant effect of the EDAR polymorphism was observed on root morphology of the other teeth.

Conclusions: Our study contributes to unravel the molecular mechanism for the formation and the diversity of the tooth morphology.