nominally significantP = 0.020
In combined‐cohort models adjusted for genetic subgroup (Sporadic/LRRK2/GBA/Other), the AD × SAA interaction at the visuospatial endpoint remained nominally significant (eg, JLO‐MSSAE P = 0.020), and leave‐one‐subgroup‐out analyses (dropping LRRK2 or GBA) yielded comparable estimates (JLO scaled measures P ≈ 0.042–0.047), indicating the signal was not driven by a single genetic subgroup despite LRRK2 contributing most SAA‐negative cases.