[nphardon]

How old is your mother? Iirc PSEN1 correlates to very early AD, like late 30s early 40s. My dad had full blown AD at 65, with serious cognitive decline starting at 63, and that felt very early to us all. My dad had no AD biomarkers on full genetic scan. My heart goes out to you and your family.

[avgDev]

She is now 63. Started showing symptoms at 61. Her sister died at 64 and her onset was in her 50s.

I am working with invitae to get her DNA tested. Unfortunately, her stage is considered moderate and very little treatment options.

[armadsen]

There are multiple specific possible mutations that cause 100% penetrant dominantly inherited early onset Alzheimer’s. And there are three genes where mutations can cause it: PSEN1, PSEN2, and APP. The average age of onset seems to depend on the specific mutation. In my (wife’s) family, onset is mid 40s to mid 50s. Some families get it even earlier, but 30s seems rare.