Meanwhile, inadequate regulation of intracellular calcium via leaky ryanodine receptor 2 (RyR2) channels and the activation of Alzheimer's disease (ad)‐like neuropathology (hyperphosphorylation of tau) have been associated with neurological symptoms, particularly the ‘brain fog’ observed in long COVID [52]. This evidence concerns the gene RYR2 and early-onset autosomal dominant Alzheimer disease.