[Hexosaminidase deficiency as differential spinocerebellar diseases].

Tay-Sachs disease is caused by Hexosaminidase A deficiency. Symptoms of the enzyme deficiency rarely become clinically manifest in adult age; then the course of the disease differs in a wide range. We report on a patient with cerebellar ataxia and lower motor neuron disease. Neurophysiological investigations, neuro-imaging (CT, MRI), and muscle biopsy reveal pathological but nonspecific findings. Determination of hexosaminidase A and B activities leads to the diagnosis. In patients with spinocerebellar ataxia hexosaminidase deficiency has to be considered as a differential diagnosis.