PTH1R and primary failure of tooth eruption: Although, the expression or function of either the E35K or Y134S mutant receptor in developing dental tissue has not been evaluated, such a LOF effect would be consistent with the findings that a number of other PTH1R mutations identified in patients with PFE lead to reduced receptor expression and function when assessed in transfected cells, including the heterozygous mutations of P132L, P119L, and G452E19,20 as well as the homozygous V204E variant we characterized previously40.