TREM2 and amyotrophic lateral sclerosis: The p.R47H mutant (associated with genetic risk of AD [13, 17–23], PD [14], ALS [24], and essential tremor [25]) showed slightly less, albeit similar patterns of cell-surface TREM2 expression, maturation, and sTREM2 generation compared with non-mutated TREM2 [72].