The invention provides a method for assessing risk of a neurodegenerative
disease or disorder in a subject. The method comprises comparing a level
of anti-.beta.-amyloid-42 (A.beta..sub.42) antibody in a biological sample
from a subject to a normal level, wherein a lower level in the biological
sample from the subject indicates the risk of the disease or disorder. In
a specific embodiment, the disease or disorder is Alzheimer's Disease
(AD).
