LAUSR

Spinocerebellar Ataxia 12(SCA12) is a rare form of SCA, predominantly reported in the ethnic Agarwal population originating from North India. It generally presents with late onset upper limb tremor followed by ataxia. Tremor in SCA12 remains poorly studied to date. Since action tremor is the most common and earliest sign in SCA12, it is often mis-diagnosed as Essential tremor. In SCA12, CAG repeat associated neuro-toxic protein accumulation accelerates degeneration in the cerebello-cortical region. Since toxic protein associated neuro-degeneration is a diffuse process, one may expect appendicular features of SCA12 to reflect symmetry. But asymmetrical hand tremor was documented in one patient of Indian origin by Kalia et al. They stated that previous reports did not comment about tremor symmetry, this remains largely true to date. In this paper we have tried to explore if asymmetry of symptoms in SCA12 is an exception or a common finding. We studied 22 cases of SCA12 with a focus on laterality and associated phenomenology of symptoms. Mean disease duration in our study population was 8.2 ( 4.7) years. Tremor was clinically analyzed by a movement disorders neurologist. The findings have been summarized in Table 1. When we look into upper limb findings, all 22 (100%) patients had intention tremor, 21 (95%) had dysmetria, 21 (95%) patients had postural tremor and 12 had rest tremor. Interestingly, postural tremor did not depict re-emergence, which is commonly seen in Parkinson’s disease. Twenty (91%) patients had asymmetrical upper limb tremor and 10 (45%) had asymmetrical dysmetria. Out of these 20 patients, 19(90%), 10 (83%) and 5 (29%) had asymmetry in