Professor Masters is distinguished for his outstanding contributions to the study of amyloid deposition in the brains of patients with degenerative brain conditions, especially in Alzheimer's disease. He purified the amyloid plaques from Alzheimer brains and cooperated with Beyreuther in determining its amino-acid sequence and in cloning the gene coding for the amyloid precursor protein, APP. Mutations of the gene, on chromosome 21, have now been shown to cause forms of familial Alzheimer's disease. The detailed study of the processing pathways involving APP has identified rational therapeutic targets for treatment of Alzheimer's disease and prevention of its onset.