THE DIFFERENTIAL-DIAGNOSIS OF ADULT-ONSET METACHROMATIC LEUKODYSTROPHY AND EARLY-ONSET FAMILIAL ALZHEIMER-DISEASE IN AN ALZHEIMER CLINIC POPULATION

Clinical differentiation between forms of progressive dementia can pro ve difficult, particularly when relatively rare forms of dementia are involved. Factors such as family history of dementia, age at onset, pr esenting features such as personality change, cognitive deficits, psyc hiatric symptoms, and clinical course (progressive deterioration; rete ntion of skills over time) may prove useful for directing investigatio ns to identify underlying pathology and genetic implications. This is illustrated by two patient reports. Each patient had the onset of memo ry/behavioral problems at approximately age 40 years, was initially gi ven a psychiatric, non-dementing diagnosis, and had a positive family history for early onset behavioral and memory problems. After longitud inal assessment, the diagnosis of Alzheimer disease was confirmed at a utopsy in one patient and a diagnosis of familial, adult-onset metachr omatic leukodystrophy in the other.