Reduced cerebellar rhythm by climbing fiber denervation is linked to motor rhythm deficits in mice and ataxia severity in patients.

Cerebellar ataxia results from various genetic and nongenetic disorders and is characterized by involuntary movements that impair precision and motor rhythm. Here, we report that climbing fiber (CF) denervation is a common pathophysiology underlying motor rhythm loss in cerebellar ataxia. By examining cerebellar pathology in patients with spinocerebellar ataxia (SCA) types 1, 2, and 6 and multiple system atrophy, we identified CF degeneration with synaptic loss as a shared pathophysiology.