FGFR2 and achondroplasia: Virtually all of the new achondroplasia mutations arise in the male germline at one nucleotide site (G1138A) in the fibroblast growth factor receptor 3 (FGFR3) gene and with a mutation frequency even higher than the C755G mutation in FGFR2. These common characteristics suggest that the G1138A mutation may also increase to such a high frequency by a selective mechanism [4,5,12,13].