Since the concept of a ‘pre-symptomatic’ eye movement disorder was previously described in children [2, 3] and adults diagnosed with SCA6 [4], the suggestion that all children with PTU, and an ocular motor apraxia or strabismus (especially when associated with developmental delay or cerebellar atrophy), should be considered for CACNA1A genetic testing. This evidence concerns the gene CACNA1A and ocular motility disease.