Cerebellar abiotrophy in an alpaca (Lama pacos).

Cerebellar abiotrophy, a premature degeneration of cerebellar neurons, has been described in most domestic animals. Affected animals typically present with progressive neurologic signs after a variable period of postnatal normalcy. This report describes the clinical, histopathologic, and immunohistochemical (IHC) findings of cerebellar abiotrophy in an alpaca. The alpaca developed intention tremors, hypermetria, and a wide-based stance at 1.5 years of age. Histologic lesions, confined to the cerebellar vermis, included marked absence of Purkinje cells, decreased granule cells, narrowing of the molecular layer, and thinning of white matter tracts consistent with abiotrophy. Increased cell processes in the molecular layer immunolabeled for glial fibrillary acidic protein, whereas immunoreactivity for neurofilament was reduced in the molecular layer and cerebellar folia white matter. To the investigators' knowledge, this is the first report of cerebellar abiotrophy in a camelid and the first documentation of IHC findings associated with this condition.