Polymyositis 1 & 2 (PM1 & PM2) – Kooikerhondje

Polymyositis is a muscle disease in which inflammation of the muscles leads to problems with walking and swallowing. This variant has been identified in the Dutch Kooikerhondje. Two DNA mutations are involved in the development of polymyositis in this breed: PM1 and PM2. Only dogs that are homozygous or heterozygous for PM1 develop the disease.
Dogs that are homozygous for the PM1 mutation have approximately a 10% chance of developing the disease, while dogs that are heterozygous for the PM1 mutation have up to a 2% chance of developing the disease.
If these dogs are also homozygous or heterozygous for PM2, the risk of developing the disease increases by 30%.