Novel presenilin-1 Y159F sequence variant associated with early-onset Alzheimer's disease

Background: Mutations in the gene for presenilin-1 cause familial, early-onset Alzheimer's disease.

Methods: We report the case of a 43-year-old woman presenting with progressive cognitive decline and a family history of early-onset dementia. Her workup included cerebrospinal fluid amyloid-beta, tau, and phospho-tau levels, as well as genetic sequencing of genes implicated in familial Alzheimer's disease.

Results: Cerebrospinal fluid biomarkers were consistent with a diagnosis of Alzheimer's disease. A novel nucleotide sequence variant (A476T) was discovered in one allele for presenilin-1, corresponding to a missense tyrosine-to-phenylalanine change at codon 159 (Y159F). An affected maternal uncle carried the same allele. The sequence variant occurs in a conserved region of the gene near other previously reported mutations.

Conclusions: This novel presenilin-1 sequence variant cosegregated with early onset dementia in the proband and at least one other affected family member, and likely represents a mutation causing familial, early-onset Alzheimer's disease.