Some members of this family are capable of discriminating between different conformational strains of PrPSc, the prion disease associated aggregate form of normal prion protein PrPC, that would be indistinguishable by immunohistochemistry alone (Sigurdson et al., 2007), while others can detect beta amyloid and tau filaments in post-mortem AD brains (Aslund et al., 2009). The gene discussed is PRNP; the disease is Alzheimer disease.