Necrotizing meningoencephalitis (NME) is an inflammatory disorder of the brain and its surrounding membranes that most commonly affects small dogs. Breeds affected include the Pug, Maltese, Chihuahua, Shih Tzu, Lhasa Apso, Boston Terrier, Papillion, Pekingese, Pomeranian, Yorkshire Terrier and West Highland White Terrier. Affected dogs can develop seizures, depression, difficulty walking, circling and blindness. The cause of NME is unknown. Dogs with NME typically develop neurological signs very quickly and often die due to a lack of ideal treatment regimens. There is no way to definitively test for NME before death. Multiple laboratories have shown NME to be inherited within families of Pug dogs, supporting a role for genetic factors in the development of this disease. The goal of this study is to characterize previously identified DNA regions of interest in order to identify specific genetic mutations that are responsible for this disorder in Pugs, Maltese and Chihuahuas. The identification of genes associated with NME will improve our understanding of the disease process, allow for the development of DNA tests and potentially more directed treatment strategies. Genetic testing ultimately should allow for a dramatic reduction in the incidence of NME through non-disruptive alteration of breeding programs.