P7-methylation status of the Runx2 P2 promoter in a family with ectopic maxillary canines.

Introduction Genetic factors contribute to the aetiology of the ectopic canine (EC) (OMIM 189490), the inheritance pattern being autosomal dominant with variable expression and incomplete penetrance. However there is also evidence for an epigenetic component [1]. The Runx2 gene is intimately involved in the mechanism of tooth eruption. It controls differentiation and maturation of osteoblasts and is expressed in the dental follicle and alveolar bone at all stages of development [2,3]. Mutations of this gene result in delayed and ectopic eruption of teeth. There is a large CpG island spanning its proximal promoter, first exon and part of the first intron. Similarities between the inheritance patterns of EC and other methylation disorders raises the hypothesis that differential methylation of the Runx2 promoter may contribute to EC.