Lafora disease in a mixed-breed dog

Case report

Abstract

Lafora disease is a rare hereditary neurodegenerative encephalopathy characterized by the intracytoplasmic accumulation of abnormal polyglucosans resulting from alterations in glycogen metabolism, associated with mutations in the EPM2A (laforin) or NHLRC1/EPM2B (malin) genes. Although described in humans and in predisposed canine breeds such as Beagle, Basset Hound, and Miniature Wirehaired Dachshund, it remains underdiagnosed in mixed-breed dogs, partly due to the reliance on histopathological or genetic confirmation, which is often performed post mortem. This report describes the case of a 10-year-old mixed-breed female dog presenting with recurrent seizures, myoclonus, ataxia, and vestibular signs, in addition to relevant comorbidities. Histopathological examination revealed PAS-positive Lafora bodies, predominantly distributed in the cerebellum and brainstem, associated with mild neuronal necrosis and diffuse gliosis. The correlation between clinical progression and anatomopathological findings allowed the diagnosis of Lafora-type progressive myoclonic epilepsy. This report highlights the importance of including Lafora disease in the differential diagnosis of chronic neurological disorders in dogs, especially in animals without a defined breed predisposition, and emphasizes the need for an integrated diagnostic approach combining clinical evaluation, complementary examinations, and histochemical analysis for definitive confirmation.