Which of the following has been shown to cause Alzheimer's disease in some patients?
a) Alcohol or drug abuse.
b) Aluminum deposits in the brain.
c) A genetic defect in some families.
d) Lack of education.
Studies indicate that a small but important percentage of Alzheimer's disease patients come from families in which the disease occurs more often than in the general population. This suggests that genetic factors play an important role in those families. Scientists have not yet been able to establish how much of a role genetics plays is the vast majority of families, however, and they have yet to identify other factors of causing the disease.