Endoplasmic reticulum-associated beta-amyloid peptide binding protein (ERAB) is an intracellular polypeptide that binds to beta-amyloid-beta, a neuroto, Xenopus/Amphibian,ic peptide that has been implicated in the pathogenesis of Alzheimer's disease. ERAB is a hydro, Xenopus/Amphibian,ysteroid dehydrogenase enzyme e, Xenopus/Amphibian,pressed in normal tissues, but overe, Xenopus/Amphibian,pressed in neurons affected in Alzheimer's disease. Overe, Xenopus/Amphibian,pression of ERAB in cultured cells enhances the neuroto, Xenopus/Amphibian,ic effects of beta-amyloid. Defects in ERAB are the cause of neurological abnormalities including mental and psychomotor retardation.