Immunogen sequence: MTELPAPLSY FQNAQMSEDN HLSNTVRSQN DNRERQEHND RRSLGHPEPL SNGRPQGNSR QVVEQDEEED EELTLKYGAK HVIMLFVPVT LCMVVVVATI. Presenilin1 was initially identified a marker of susceptibility to early-onset Alzheimer's disease. In addition to PEN2, ni