Sensory ataxic neuropathy (SAN) is a recently identified neurological disorder in golden retrievers...The mutation could be traced back to a common ancestor of all affected dogs that lived in the 1970s...SAN has an insidious onset during puppyhood, followed by slow progression. Males and females are affected at similar frequencies. Affected dogs are ataxic, have postural reaction deficits and reduced or absent spinal reflexes. They have no pronounced muscle atrophy, and the dogs do not seem to be in pain. Electrophysiological examination revealed that they have reduced conduction velocities of nerve impulses in sensory nerves. Pathological examination indicated degenerative changes both in the central and peripheral nervous system. Approximately fifty percent of the affected dogs were euthanized before three years of age...(From Baranowska et al, 2009)