Three-year follow-up of a patient with early-onset Alzheimer's disease with presenilin-2 N141I mutation - case report and review of the literature.

Autosomal dominant early-onset Alzheimer disease (EOAD) is a heterogeneous condition that has been associated with mutations in 3 different genes: the amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) genes. Most cases are due to mutations in the PSEN1 gene, whereas mutations in the APP and PSEN2 genes are rare. Mutation analysis of the APP, PSEN1 and PSEN2 genes was performed. We herein report the case of a German EOAD patient with a family history of dementia and a missense mutation at codon 141 (N141I) of the PSEN2 gene. To our knowledge, this is the first German EOAD patient without a Volga-German ancestry and a positive family history for dementia carries the mutation PSEN-2 N141I. The patient came to our clinic for the first time when she was 47 years old. During the following 3 years, her Mini-Mental State Examination (MMSE) score dropped from 28 to 0. Mild cognitive impairment (MCI) was an early symptom that was already present during the first consultation. The concentration in cerebrospinal fluid (CSF) of tau-protein (1151 pg/ml) was increased, whereas the concentration of beta-amyloid protein (Abeta1-42) was decreased (335 pg/ml). Magnetic resonance imaging (MRI) revealed only slight changes in the early stage of the disease and positron emission tomography with (18F) fluoro-2-deoxy-D-glucose (18F-FDG PET) demonstrated glucose reduction left parietal and in the precuneus region. Follow-up MRI and 18F-FDG PET studies showed progression of atrophy of the left entorhinal cortex with relative sparing of the hippocampus and progressive hypometabolism of both temporoparietal lobes and left frontal lobe.