Leucoencephalomalacia and cerebral white matter vacuolar degeneration in two related Labrador retriever puppies.

Two Labrador Retriever dogs from a common dam had similar neurological deficits consisting of cortical blindness, dullness, and loss of previously learned habits. Both were examined at 5 months of age, and histopathological examination revealed leucoencephalomalacia and vacuolar degeneration of the cerebral white matter. Histopathologic findings in these 2 dogs differed from those reported previously in Labrador Retrievers with spongy degeneration of central nervous system white matter. A nonlittermate full sibling to 1 of these dogs was examined at 1.5 years of age for similar clinical signs that did not progress for the next 25 months.