Cognizant of the long history of a possible role for Ca2+ abnormalities in Alzheimer’s disease, we further looked into that disorder, as well as PTSD, and found roles for leaky RyR2 channels in both (26, 28); more recently, we found possible involvement in the brain fog associated with long COVID (52). Here, RYR2 is linked to early-onset autosomal dominant Alzheimer disease.