It is a Genetic deformity, but do not think of it as a negative. Without "genetic deformities" we would have no polydactile cats, nor would we have Curled eared cats, or my love of loves Bobtails! Try not to see it as a negative but just something different. Remeber, the things that make us different are the things that make us Love. If everything were the same we would feel the same about everything.