Early-Onset Dementia-Parkinsonism with Rapid Development of Motor Fluctuations and Dyskinesia Due to PSEN1 G206V Pathogenic Variant

Abstract

Pathogenic variants in the Presenilin 1 gene (PSEN1, OMIM#607822) represent the most frequent cause of Dominant Inherited Alzheimer's disease (DIAD),1 with more than 200 pathogenic variants reported and associated with an age at onset before 50 years, with some cases reported even before 40.2 Movement disorders, mainly myoclonus and parkinsonism, can occur in the early course of the disease and affect up to 30% of patients.2, 3 Furthermore, some of the cases with parkinsonism have been reported to be levodopa-responsive and to develop early motor fluctuations and dyskinesias.4 However, PSEN1 variants are seldom considered in the assessment of patients with early-onset parkinsonism.5 We describe the case of a patient with a mixed clinical phenotype of early-onset dementia and parkinsonism with motor complications due to a pathogenic variant in the PSEN1 gene...