In summary, we have identified eight new loci affecting primary tooth eruption, which together with previously identified loci explain 6.06% of the variation in ‘age of first tooth’ and 4.76% of the variation in ‘number of teeth’. These estimates compare favourably with larger studies on human height; for example, using a total sample size of 39 509, Gudbjartsson et al. discovered 27 loci associated with human height, which together explained 3.7% of the variation in human height (27). Several of these variants also appear to exhibit pleiotropic actions, including effects on craniofacial development, height and potentially on disease development in later life. Furthermore, we report a number of genes belonging to pathways involved in growth/development and cancer. A thorough understanding of how the functional variants underlying these associations mediate their effects is likely to yield rich rewards not only in terms of understanding tooth eruption and craniofacial development, but also potentially about how disease develops across the life course.
