Munchkin

In cats, as in most animals, the mutation only affects the size of the legs and has no impact on the head, hands or feet, as is the case in humans, although it is the same gene responsible for the mutation: genetic studies agree that this is a form of dwarfism caused by a new autosomal dominant dwarfism gene, UDP-glucose 6-dehydrogenase (UGDH). Veterinarians, geneticists and feline associations continue to carefully examine the breed, mainly to avoid drift. This is particularly the case of the LOOF which organizes 'breeding specials' several times a year to monitor the evolution of the breed. Fearing that the gene would develop in the cat as it developed in humans and affect the joints leading to cases of severe arthritis because its shorter limbs could affect its activity level, as early as 1995, several breeders had radiographs taken of their oldest munchkins and examined them for signs of joint or bone problems, without finding any. Recently, a study conducted by Dr. Lisa M. Anderson, Derek B. Fox, and several other researchers from the University of Missouri on American munchkins from several breeders proved that the munchkin condition leads to greater use of joints, which allows less arthritis, even at an advanced age. The elderly cats observed in the context of studies demonstrated a 'normal anatomical position' of the vertebrae and no spinal deformity, that is to say no lordosis (excessive curvature of the spine), which suggests that the munchkin is not more handicapped by its short legs for jumping, running or hunting than an otter, a ferret or any other mustelid naturally equipped with short legs. Although some still claim otherwise, this contradicts earlier observations. The Anderson & all. study further showed that the feline phenotype is devoid of malformations commonly associated with achondroplasia (particularly human). The scientists observed no pectus excavatum (sunken chest), noting a 'normal evaluation of thoracic limbs' in all examined subjects, nor any difference or twist in the alignment of the frontal plane of the humerus between normal cats and dwarf cats studied. New studies are regularly carried out to continue to identify potential problems in the breed, notably the research since 2012 by Dr. Leslie Lyons (associate professor at the University of Missouri College of Veterinary Medicine), who helped map the UGDH gene and its involvement in dwarfism, or the study of breeders conducted by the French breed club, whose results have not yet been released. However, geneticists, specialists and veterinarians who have studied the breed agree on cautioning breeders, but also owners, about drift that tends to multiply mutations in the same cat (in particular by marrying for example the munchkin with other breeds whose mutation affects hair or cartilage, osteochondrodysplasia in particular) and not to try to select the shortest possible legs in order to produce a hypertype).