Sandhoff disease mimicking adult-onset bulbospinal neuronopathy.

A 32 year old male is described with an onset of upper limb postural tremor in adolescence followed by muscle cramps. Progressive proximal amyotrophy and weakness in the limbs developed late in the third decade. Examination disclosed, in addition, bilateral facial weakness and mild dysarthria. Enzyme studies revealed hexosaminidase A and B deficiency, indicating a diagnosis of Sandhoff disease. Intra-axonal membranocytoplasmic bodies were present in a rectal biopsy. The presentation, which resembled that of X-linked bulbospinal neuronopathy, widens the clinical spectrum for disorders related to G(M2) gangliosidosis.