Late adult-onset metachromatic leukodystrophy. Dementia and polyneuropathy in a 63-year-old man.

A diagnosis of adult-onset metachromatic leukodystrophy (MLD) was established in a living 63-year-old man with progressive dementia and peripheral neuropathy. Decreased nerve conduction velocities and elevated spinal fluid protein concentration led to more specific diagnostic studies required to confirm the diagnosis. This case expands the spectrum of adult-onset MLD to patients with dementia and polyneuropathy past the sixth decade of life. Measurement of nerve conduction velocities may help to uncover cases of adult-onset MLD and should be included in the evaluation of dementia.