by Nicole Cook

Created on: February 12, 2009

While not much is known about this relatively new breed, the most notable difference in the breed that sets it apart from the rest is their abnormally short legs. While not yet confirmed or proven, the breeds' short legs may be caused by a genetic mutation that results in achondroplasia, a type of autosomal dominant genetic disorder, which is the common cause of dwarfism in humans. Achondroplasia is a congenital disorder that is a result of an autosomal dominant mutation in the fibroblast growth receptor gene 3 causing a malformation of cartilage. Munchkin cats have one normal copy of the gene and one mutant copy. Being born with two copies of the mutant gene results in inevitable death either at birth or soon after.

Since the head of a munchkin cat is not affected by the mutation as it is in humans, the breeds' mutation should be more appropriately termed Hypochondroplasia, a developmental disorder caused by the same mutated gene. Hypochondroplasia results from mutations in the proximal tyrosine kinase domain of the fibroblast growth receptor gene 3 (FGFR3). FGFR3 "plays an important role in embryonic development, playing a part in regulating activities such as cell division, migration, and differentiation" (1) Because munchkin cats can pass the mutated gene onto their offspring, litters of kittens that stem from parents where one of the parents is a Munchkin can all be born completely normal, all munchkins or a mixture of both normal and munchkin. If both parents are munchkins their litters will have one of four results, either a litter of completely normal kittens, a litter of all munchkin kittens, a litter of munchkin cats that contain two mutated genes which who will either be born deceased or die soon after birth, or some combination of all three possibilities.

The Munchkin breed originated in 1983 when a black cat with abnormally short legs was found underneath a trailer in Louisiana. The cat was pregnant and gave birth to a litter of kittens, half of which had the same abnormally short legs. One of the short-legged male kittens later became the source of a breeding program that helped to develop the breed in North America. Many organizations refuse to recognize the short-legged breed and consider the breeds' appearance to be the result of a disease which should not be intentionally reproduced. On the other side there are many breeders and owners who state the breed is healthy and a "sound breed" that is no more susceptible to disease or illness than any other breed.

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />References:
1. http://en.wikipedia.org/wiki/Achondroplasia
2. http://en.wikipedia.org/wiki/Munchkin_(cat
3. http://en.wikipedia.org/wiki/Achondroplasia

Learn more about this author, Nicole Cook.
Click here to send this author comments or questions.