Cerebellar atrophy and muscle weakness: late-onset Tay-Sachs disease outside Jewish populations

A 47-year-old Caucasian man of non-consanguineous parents presented with a slowly progressive gait disorder and falls. Disease manifestations were present since early childhood with mild motor and mental retardation. Slowly progressive cerebellar ataxia, proximal muscle weakness and atrophy, mild cognitive decline and incomplete ophthalmoplaegia developed in late adolescence. At the time of presentation, he was still able to walk unaided for short distances. MRI of the brain (figure 1A, B) revealed marked cerebellar atrophy. The brainstem appeared unaltered. There were no white matter abnormalities. Nerve conduction studies were normal. Electromyography …