Congenital cerebellar dysfunction in dogs does not occur too commonly but one will see a case occasionally in practice. This case is about a female papillon puppy that presented with a long progressive history of cerebellar dysfunction and inappetence and a more recent history of seizures and vestibular episodes that consisted of falling over, losing her bowel movements, and nystagmus. Her neurologic exam was consistent with cerebellar dysfunction as well as cervical pain. Bloodwork analysis for a minimum database showed no evidence of extra-cranial disease such as juvenile hypoglycemia or a po1io-systemic shunt. An MRI was performed and showed diffuse and symmetrical hyperintensity on T2- weighted images. The hyperintensity was most pronounced on the subcortical white matter at the junction of the white and gray matter in the cerebrnm, the cerebellar nuclei, and the brainstem gray matter. Cerebrospinal fluid analysis was normal and a metabolic screening panel showed no evidence of an inborn error of metabolism. However, the urine metabolic screening panel does not test for all lysosomal storage diseases. Given the history, neurologic exam findings, and diagnostic tests; the presumptive diagnosis is GMl gangliosidosis; however, neuroaxonal dystrophy is still a possibility. GMl gangliosidosis is an inherited lysosomal storage disease characterized by a deficiency ofbeta-galactosidase and buildup of the substrate called ganglioside within neurons. The patient is being medically managed with Levatiracetam to control her seizures and Meclizine for the nausea associated with her vestibular disease to improve her appetite. She has improved dramatically on these medications; however, prognosis is still guarded long term.