Cyclic Neutropenia (CN) is also known as Cyclic Hematopoiesis or "Gray Collie Syndrome." CN affects the neutrophils of a dog, which are an integral part of the dog's immune system. In a cycle of 10-12 days, the dog will experience a dramatic drop in the number of neutrophils circulating through the blood stream, leaving them extremely susceptible to infections. This can manifest as diarrhoea, fever, joint pain or eye, respiratory, or skin infections. Bleeding episodes can also occur. Puppies who are affected will appear visibly lighter in colour than non-affected littermates. This also applies to merle pups. Age of onset from birth/puppyhood, and sadly most affected dogs will die as puppies. Even with optimum care, dogs don't live beyond 2-3 years of age.