A novel PSEN1 (p.Gln223Leu) variant associated with spastic paraparesis and early-onset Alzheimer's disease.

We report a novel PSEN1 likely pathogenic variant associated with spastic paraparesis (SP) preceding cognitive decline. A 41-year-old man with a two-year history of SP followed by cognitive impairment one year later, was found to carry a heterozygous PSEN1 c.668A > T (p.Gln223Leu) variant. Alzheimer's disease (AD) was confirmed with a combination of low CSF Aβ42 levels and amyloid positivity on [18F]Florbetaben PET. This case represents the third reported association between substitutions at PSEN1 codon 223 and AD with SP, emphasizing the need to consider PSEN1 mutations in cases of SP preceding cognitive decline.