Abbreviations: Aβ42/40 = amyloid-beta42/40 ratio, AD = Alzheimer’s disease, GFAP = glial fibrillary acidic protein, NfL = neurofilament light chain, t-tau = total tau, p-tau181 = tau phosphorylated at threonine 181, p-tau231 = tau phosphorylated at threonine 231. This evidence concerns the gene GFAP and early-onset autosomal dominant Alzheimer disease.