The mis-sense mutations were Met-452-->Thr in 17 cats (35 nodules), Ser-504-->Arg (two different mutational forms) in two cats (two nodules), Val-508-->Arg in one cat (three nodules), Arg-530-->Gln in one cat (two nodules), Val-557-->Leu in 13 cats (36 nodules), Thr-631-->Ala or Thr-631-->Phe (each mutation seen in one nodule of one cat), Asp-632-->Tyr in six cats (10 nodules) and Asp-632-->His in one cat (one nodule).