Multimodal PET/MR Imaging in Early-onset Alzheimer's Disease With Parkinsonism due to a Novel Presenilin-1 (M233I) Mutation.

We report the multimodal PET/MR imaging findings in a 31-year-old woman with a novel presenilin 1 (PSEN1) missense mutation (c.699G>A, p.M233I) who developed progressive cognitive decline and parkinsonian features. Multimodal imaging, including glucose metabolism, dopamine transporter function, amyloid-β pathology, and tau protein PET imaging, combined with structural MRI, revealed widespread abnormalities concordant with her clinical manifestations. Findings included glucose hypometabolism, dopaminergic dysfunction, amyloid and tau deposition, and cerebellar atrophy. This case highlights the diagnostic value of multiprobe PET/MR imaging in characterizing complex neurodegenerative phenotypes and expands the genotypic and phenotypic spectrum of PSEN1 -associated early-onset Alzheimer's disease (EOAD) with parkinsonism.