[Genetic predisposition to Alzheimer's disease]

Alzheimer's disease can present either as an early-onset or senile dementia. Its ethiology is heterogeneous but with common clinical and pathological features.

Alzheimer's syndrome can occur with familial clustering. Some families with pre-senile dementia have shown three different genes which are associated with the pathological features. These genes carry on several mutations which have an autosomal dominant transmission: each mutation seems to be able to cause the pathological changes. The senile dementias are more common but dominant transmission has not been shown. However, risk genetic factors can play a rol. The epsilon 4 allel for apolipoprotein E has been clearly identified.

It would be possible to use genetic tests to predict the appearance of presenile dementias but these tests are not available for the more common senile types of Alzheimer's dementia.