The invention provides an isolated nucleic acid characteristic of human
amyloid precursor protein 770 including the nucleotides encoding codon
670 and 671, wherein the nucleic acid encodes an amino acid other than
lysine at codon 670 and/or an amino acid other than methionine at codon
671. Also provided is a method of diagnosing or predicting a
predisposition to Alzheimer's disease, comprising detecting in a sample
from a subject the presence of a mutation at a nucleotide position
corresponding to codons 670 and/or 671 of amyloid precursor protein or
fragment thereof, the presence of the mutation indicating the presence of
or a predisposition to Alzheimer's disease.
