Alzheimer’s disease is a relentlessly progressive neurodegenerative disorder that affects between 5% and 7% of adults over 60.1 For a small number, early-onset Alzheimer’s is caused by mutations either in the APP, or Presenilin 1 and 2 genes (PS1 and PS2)2 with an autosomal dominant mode of inheritance. The gene discussed is PSEN1; the disease is Alzheimer disease.