Bunny hopping syndrome (BHS1) in the Weimaraner breed is an autosomal recessive inherited movement disorder due to a neurological developmental defect.

In mammals, one half of the brain always supplies the other half of the body, i.e. nerve fibers from the left half of the brain innervate the right half of the body and vice versa. To ensure that the movement control functions correctly, nerve pathways in the spinal cord must only ever run on one side of the body. In dogs with BHS1, this strict order is disrupted and nerve pathways in the spinal cord switch sides. As a result, the dogs are not able to specifically control either the left or the right hind leg, but always hop with both legs. Because this gait resembles the hopping of a bunny, the disease is called bunny hopping syndrome. Unlike shaking puppy syndrome in Weimaraners, the gait of puppies affected by BHS1 does not improve, which usually leads to euthanasia as there is no cure.