It has been known for some time that mutations in the PTH1R gene are a significant cause of autosomal dominant PFE in humans.22 Since the original discovery of a link between PFE and PTH1R function, more than 50 variants in this gene have been identified in association with PFE.23 However, PTH-related signalling currently remains the only known candidate pathway identified in primary eruption failure. The gene discussed is PTH1R; the disease is primary failure of tooth eruption.