The Munchkin is a fairly new breed of cat with a lot of controversy surrounding it. The breed is created by a mutation that causes achondroplasia, or hypochondroplasia, which results in the cats having abnormally short legs. The breed originated when a pregnant, short-legged black cat was discovered in Louisiana in 1983. One of her kittens, a tomcat, became the father of the breeding program for Munchkins.
Several cat registries refuse to recognize the breed due to the controversy that surrounds the genetic mutations. Some argue that the mutation is abnormal and potentially harmful to the cat. Some breeders say it is an ideal breed that is no more susceptible to health problems than any other feline.
The genetic abnormality which causes their short legs is often referred to as achondroplasia, however it has not yet been proven that the short-legged trait is due to a gene at the same locus as causing achondroplasia in humans. The abnormality is instead often referred to as hypochondroplasia so as not to be associated with enlarged heads and short legs like achondroplasia.
Munchkins are more prone to lordosis and pectus excavatum than most other cats.
The munchkin gene is autosomal and dominant. Only heterozygous munchkin cats are able to pass on the gene. All litters with at least one munchkin parent have the possibility of containing all normal, all munchkin or a combination of munchkin and normal kittens. Litters with two munchkin parents may be all normal, all munchkin or all stillborn.