TREM2 and Alzheimer disease: Such contributions include our previous studies of a Turkish dementia cohort where we described mutations in the known Mendelian AD genes [13], a NOTCH3 variant, known to be causative for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, in an AD case [14], three homozygous TREM2 variants and a compound heterozygous variant in FTD-like families [15, 16], and no variants or CNVs in TYROBP/DAP12, which encodes a TREM2 ligand [17].