Our findings should indicate that a T666M mutation of CACNA1A may be associated with more variable clinical features and that paroxysmal hemiplegic migraine attacks and progressive cerebellar atrophy should have distinct mechanisms of pathogenesis.
For the efficient screening of SCA6, we would propose testing CAG repeat expansion in CACNL1A4, in patients with one of two markers: (1) horizontal or oblique gaze nystagmus without other eye movement disorders, (2) pure cerebellar atrophy, even if occurrence is sporadic.
In SCA6, a mild reduction in the ratio of the ventral pontine area to the posterior fossa area (Pv/PF) was observed as well as obvious cerebellar atrophy.
A clinical, genetic, neuropathological study in a Japanese family with SCA 6 and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy.