Novel PS1 mutation in a Bavarian kindred with familial Alzheimer disease.

We describe a novel Leu174Arg PS1 mutation in two members of a Bavarian family which were initially diagnosed with frontotemporal dementia. Intriguingly, there is the possibility that there is an 18th century founder effect and that this family is related to original kindreds with familial Alzheimer disease described in the early 20th century.