APP Ala713Thr was observed once in our AD cohort and despite being reported as pathogenic in the literature, its population frequency suggests low penetrance for EOAD of 0.4% (95% CI 0.1–2.4%), MAPT Gly389Arg (observed twice in our data set) was estimated to have 10.2% penetrance (95% CI 1.6–63.5%) and PSEN1 Ile227Val (observed once in our data set) was estimated to have 2.9% penetrance (95% CI 0.3–26.9%) (See Tables 1S–3S for more details). Here, PSEN1 is linked to Alzheimer disease.