Hypomyelination is an inherited neurologic disease affecting dogs. Affected dogs develop generalized tremors between 1 to 3 weeks of age. Affected puppies are able to walk but often have a hopping type of gait in the hind limbs. Tremors are not present when puppies are at rest or asleep, and there is often variation in severity even between affected littermates. Though the tremors typically improve by 3 to 4 months of age, severely affected puppies may be euthanized within the first few weeks of life. Additionally, a fine tremor of the hind limbs can persist as the dog ages.