The ataxic Syrian hamster: an animal model homologous to the pcd mutant mouse?

A spontaneous model of cerebellar ataxia in the Syrian hamster is described. Breeding data indicate that the condition is hereditary and that the mode of inheritance is autosomal recessive. Homozygotes are smaller in size than the wild-type but have a normal appearance. Mutants show a moderate ataxia beginning at 7 weeks of age. Although affected adults exhibit significant atrophy in the cerebellum, other parts of the brain appear relatively normal by light microscopy. Mutants lose almost all Purkinje cells by 18 months of age and exhibit a moderate reduction in granule cell density, probably as a consequence of the primary loss of Purkinje cells. In the homozygous hamster brain, Nna1 expression is suppressed, similar to that previously observed in Purkinje cell degeneration (pcd) mutant mice. A phenotypic comparison of ataxic hamsters with the pcd mutant mice suggests that the influence of the causal allele in ataxic hamsters is considerably milder than most of the alleles found in the mutant mice.