Slowed abduction during smooth pursuit eye movement in episodic ataxia type 2 with a novel CACNA1A mutation

- Slowed abduction during smooth pursuit (pursuit abduction lag) is rare.
- This is the first case of EA2 presenting with pursuit abduction lag.
- Our case exhibited cerebellar oculomotor signs and dissociated nystagmus.
- Brainstem and cerebellar dysfunction could contribute to pursuit abduction lag.
- A novel nonsense mutation might be associated with this rare phenotype.