GME, or granulomatous meningoencephalomyelitis, is a common neurologic disease in dogs, yet its cause is unknown and no cure exists.

An inflammatory condition of the nervous tissue, it usually involves the brain, but can also affect the spinal cord and its covering, called the “meninges.”

“This condition is also part of the class of CNS inflammatory diseases known as meningoencephalomyelitis of unknown etiology (MUE). It is difficult to distinguish GME from other breed-specific inflammatory disorders and infectious diseases,” says Joan R. Coates, D.V.M., M.S., DACVIM, a professor of neurology and neurosurgery at the University of Missouri College of Veterinary Medicine in Columbia. It’s more common in smaller dog breeds, particularly Toys, Poodles and the smaller Terriers, and strikes at a median age of 5. However, no statistics exist as to how many dogs are diagnosed each year with GME.

While there may be an as-yet unproven, underlying genetic predisposition, it’s also thought that infectious agents may underlie GME. Despite the development of different types of tests, researchers have been unable to find a “consistent underlying infectious cause,” Coates says. However, infectious diseases of the brain can look like GME. “So it’s very important to rule out other infectious causes like viral, tick-borne diseases and fungal diseases.”