2009 Volume 62 Issue 2 Pages 148-154
In a litter of three Japanese domestic short hair cats，two showed cerebellar ataxia，with decreased residual lysosomaｌ β-galactosidase activity. Membranous cytoplasmic bodies were also observed electron microscopically in the medulla of the affected cats. The two cats were diagnosed with homozygous GM1-gangliosidosis，because the other cat without ataxia had intermediate residual enzyme activity between those in normal and affected cats，diagnosed with heterozygous GM1-gangliosidosis. In brainstem auditory evoked potential testing，the prolongation of peak latencies and the elevation of thresholds in waves I and V were observed in some cats. However， consistent abnormal findings observed in two affected cats included a fall in the amplitude ratio of wave I and V (I/V AR)， which may imply conductive hearing loss， and a prolongation of the interpeak latency between wave I and V (I-V IPL)，which reflects brainstem dysfunction. Brainstem function estimated by BAEP testing did not deteriorate with the stage of the disease， and higher brain function was not affected，although neurologic impairment such as central spontaneous nystagmus or swallowing difficulty progressed during the terminal stage.