To study the function of FGFR3 in bone growth and to create animal models for the FGFR3-related inherited skeletal disorders, Li et al. (1999)introduced a lys644-to-glu (K644E) point mutation, which corresponded to the lys650-to-glu mutation (K650E; 134934.0004) found in TD2 patients, into the murine Fgfr3 gene using a knockin approach