THUR 101 SCA-1 with unusual early dysautonomia and delayed cerebellar signs

Abstract

A 59-year-old right-handed bus driver presented with gradually worsening erectile dysfunction, urinary frequency and nocturia over 18 months. He had a past medical history of hypertension with regular medications including amlodipine, aspirin and atorvastatin. Initial examination revealed a mild bilateral intention tremor.The patient had undergone brain imaging showing brainstem and cerebellar atrophy with a ‘hot cross bun sign’. The patient was then referred for autonomic function tests that demonstrated mild cardiovascular autonomic changes, and suggested sympathetic dysfunction. A working diagnosis of multiple system atrophy (MSA) was made.Over the next two years, his tremor worsened with the development of slurred speech and unsteady gait. On examination, he had prominent fasciculations and wasting in the right shoulder, severe bilateral intention tremor with past-pointing. In addition he had Parkinsonism and signs of a sensorimotor neuropathy.This atypical clinical evolution with prominent neuropathy and cerebellar signs led to investigations for spinocerebellar ataxia (SCA), particularly type 2 or 3 (given the autonomic dysfunction). However, the genetic testing showed a mutation in ATXN1, confirming a diagnosis of SCA type 1.To our knowledge, this is the first reported case of prominent early autonomic dysfunction associated with SCA type 1.