CHI3L1 and frontotemporal dementia: Genetically, our results suggest that this pathway is not determined by variants in the APOE locus, but instead by variants in TMEM106B and potentially CHI3L1. TMEM106B affects neuronal loss [54] and has been convincingly associated with risk for at least two forms of dementias, i.e., fronto-temporal dementia (FTD) [54] and AD [13, 42, 55].