Atypical Early-Onset Alzheimer's Often Misdiagnosed

Many early-onset Alzheimer's patients have no memory loss, may be incorrectly diagnosed

TUESDAY, May 17 (HealthDay News) -- Patients with early-onset Alzheimer's disease (EOAD) who have atypical (non-memory) presentations, are frequently misdiagnosed, according to a study published in the May 17 issue of Neurology.

Mircea Balasa, M.D., from the Institut d'Investigació Biomèdica August Pi i Sunyer in Barcelona, Spain, and colleagues examined the clinical features, apolipoprotein E (APOE) genotype, and pathologic correlates of neuropathologic confirmed EOAD. Clinical data were collected from 40 patients who had onset of EOAD at an average age of 54.5 years, disease duration of 11 years, and an average diagnostic delay of 3.1 years.

The investigators identified non-memory presentation in 37.5 percent of patients, with behavioral/executive dysfunction being the most common atypical presentation. In patients with atypical presentations, 53 percent had incorrect initial clinical diagnoses, compared to 4 percent misdiagnosis when anterograde amnesia was the presenting symptom. Typical and atypical presentations did not show significant differences in APOE genotype, with 59 percent of patients having APOE genotype ε3/ε3. Patients with a family history of Alzheimer's disease were 3.3 times more likely to have APOE ε4. Advanced neurofibrillary pathology was seen in 97.5 percent of patients, and 45 percent had concomitant Lewy body pathology that was localized in most cases and did not have a significant clinical correlate.

"One-third of patients with pathologic confirmed EOAD presented with atypical symptoms. Patients with EOAD with nonamnestic presentations often receive incorrect clinical diagnoses," the authors write.

One of the study authors disclosed financial ties with the pharmaceutical industry.

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