Carbonic anhydrase-related protein VIII (CA8) is an IP<sub>3</sub>R1-regulating protein abundantly expressed in cerebellar Purkinje cells and is a causative gene of congenital ataxia.
The sensorimotor cerebellum is represented in the anterior lobe with a second representation in lobule VIII, and lesions of these areas lead to the cerebellar motor syndrome of ataxia, dysmetria, dysarthria and impaired oculomotor control.
A mutation in the CA8 gene has been associated with ataxia, mild mental retardation and quadrupedal gait in humans and with lifelong gait disorder in mice, suggesting an important role for CARP VIII in the brain.