Recent research, utilizing positron emission tomography (PET) analysis on CSF samples from Alzheimer’s disease (AD) patients, identified three distinct phosphorylated tau (p-tau) epitopes, including p-tau 181, p-tau 217, and p-tau 231, evident across clinical, preclinical, and pre-amyloid phases of AD [37,38]. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.