sentences:  In BHD-associated kidney tumors, the inherited "FLCN" gene with a germline mutation is present in all cells, but the remaining wild type copy is inactivated in the tumor cells through somatic mutation or loss of heterozygosity.Naturally-occurring dog and rat models with germline "Flcn" mutations develop kidney tumors that retain only the mutant copy of the gene.Homozygous inactivation of "Flcn" in these animal models is lethal to the embryo.