Hypomyelination, or 'shaky puppy syndrome,' is a central nervous system disorder that may occur in Weimaraners when the fatty protective layer of nerves—called myelin—is too thin. Nerves are important to muscle function, so a myelin deficiency may cause tremors, lack of coordination, or balance issues. Symptoms of shaky puppy syndrome usually present by 2 weeks of age. Puppies showing symptoms would undergo a series of physical exams, x-rays, and procedures to rule out other medical conditions that could cause tremors—hypomyelination can be diagnosed only in a post-mortem examination of the spinal cord. Certain breeds—Weimaraners, Springer Spaniels, Dalmations, Vizslas, and Golden Retrievers, to name a few—are more likely to be affected by shaky puppy syndrome. It is more common for male puppies to present hypomyelination, but females may be affected as well. While most puppies improve by around one year old, tremors may be present through adulthood. Dogs with hypomyelination should not be bred, as it is a hereditary condition.