Multiple multi-omic and proteomic studies support the existence of distinct biological subtypes in Alzheimer's disease, though some fluid biomarker research suggests continuous variation.
The claim that Alzheimer's disease has distinct biological subtypes is strongly supported by multiple recent high-throughput proteomic, cerebrospinal fluid, epigenomic, and transcriptomic studies that consistently identify patient subgroups (ranging from 2 to 5 subtypes) with distinct molecular pathways, genetic risk profiles, and clinical progression patterns. While one large plasma proteomic study argues for continuous molecular variation over discrete classes, the convergence of brain tissue, CSF, and cellular profiling heavily favors biological heterogeneity with distinguishable subtypes.