Comparison of cerebrospinal fluid biomarkers of Alzheimer’s disease pathology, namely amyloid beta 42, phosphorylated tau and total tau, did not reveal any significant differences between the two clusters in neither ADNI nor NACC (Mann–Whitney U test P > 0.05 for all biomarkers in both cohorts). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.