Question: Is TREM2 associated with Alzheimer's disease?

Context:
Absence of TREM2 polymorphisms in patients with Alzheimer's disease and Frontotemporal Lobar Degeneration
 These data demonstrate that TREM2 coding region is highly conserved, implying a crucial role of this receptor. Further studies, including a functional analysis, are certainly required to clarify the role of TREM2 in neurodegenerative processes
Moreover, a rare TREM2 exon 2 variant (p.R47H) was reported to increase the risk of Alzheimer's disease (AD) with an odds ratio as strong as that for APOEε4
We observed an enrichment of rare variants across TREM2 in both AD and FTD patients compared to controls, most notably in the extracellular IgV-set domain
None of the rare variants individually reached significant association, but the frequency of p.R47H was increased ~ 3-fold in both AD and FTD patients compared to controls, in line with previous reports
Our data corroborate and extend previous findings to include an increased frequency of rare heterozygous TREM2 variations in AD and FTD, and show that TREM2 variants may play a role in neurodegenerative diseases in general.
non-synonymous genetic rare variant, rs75932628-T (p.R47H), in the TREM2 gene has recently been reported to be a strong genetic risk factor for Alzheimer's disease (AD)
These data strongly support the important role of p.R47H in AD risk, and suggest that this rare genetic variant is not related to FTD.
 Higher levels of TREM2 mRNA (p = 0.002) and protein (p < 0.001) were identified in AD patients
Our results indicate that TREM2 might serve as a novel noninvasive biomarker for AD diagnosis
studies have identified the rs75932628 (R47H) variant in TREM2 as an Alzheimer's disease risk factor with estimated odds ratio ranging from 2.9 to 5.1
This study replicates the association between R47H and Alzheimer's disease risk in a large, population-based sample, and estimates the population frequency and attributable risk of this rare variant
Moreover, mutation scanning of the five exons of TREM2 failed to detect the presence of novel polymorphisms
A rare missense mutation (rs75932628-T) in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2), which was predicted to result in an R47H substitution, was found to confer a significant risk of Alzheimer's disease in Iceland
We also found that carriers of rs75932628-T between the ages of 80 and 100 years without Alzheimer's disease had poorer cognitive function than noncarriers
Our findings strongly implicate variant TREM2 in the pathogenesis of Alzheimer's disease. Given the reported antiinflammatory role of TREM2 in the brain, the R47H substitution may lead to an increased predisposition to Alzheimer's disease through impaired containment of inflammatory processes
rs75932628-T variant of the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) has recently been identified as a rare risk factor for late-onset Alzheimer's disease (AD)
These results confirm the association between this variant and AD and underline its involvement in early-onset cases
recent studies have reported the association of rs75932628-T in the TREM2 gene with the risk for Alzheimer's disease (AD)
Rs75932628-T is a rare nonsynonymous variant (p.R47H) that confers a high risk of AD with an effect size similar to that of the APOE ɛ4 allele
Here, we report the first positive replication study in a Spanish population and confirm that TREM2 rs75932628-T is associated with the risk for AD
works have demonstrated a rare functional variant (R47H) in triggering receptor expressed on myeloid cells (TREM) 2 gene, encoding TREM2 protein, increase susceptibility to late-onset Alzheimer's disease (AD), with an odds ratio similar to that of the apolipoprotein E ε4 allele
The reduced function of TREM2 was speculated to be the main cause in the pathogenic effects of this risk variant, and TREM2 is highly expressed in white matter, as well as in the hippocampus and neocortex, which is partly consistent with the pathological features reported in AD brain, indicating the possible involvement of TREM2 in AD pathogenesis
Emerging evidence has demonstrated that TREM2 could suppress inflammatory response by repression of microglia-mediated cytokine production and secretion, which may prevent inflammation-induced bystander damage of neurons
TREM2 also participates in the regulation of phagocytic pathways that are responsible for the removal of neuronal debris
Based on the potential protective actions of TREM2 in AD pathogenesis, targeting TREM2 might provide new opportunities for AD treatment
Under the hypothesis that low-prevalence variants showing moderate-to-high effect size may be associated with risk for sAD, two independent research groups have demonstrated that a rare variant (rs75932628, encoding a substitution of arginine by histidine at residue 47 (R47H), in the TREM2 gene, which encodes the triggering receptor expressed on myeloid cells 2) is significantly associated with an increased susceptibility to sAD
Recently, a novel variant in the gene encoding the triggering receptor expressed on myeloid cells 2 (TREM2) has been identified that has refocused the spotlight back onto inflammation as a major contributing factor in AD
TREM gene cluster, a region recently reported to harbor rare variants that increase AD risk
evidence suggests that rare genetic variants within the TREM2 gene are associated with increased risk of Alzheimer's disease
These data suggest that a mutational burden in TREM2 may serve as a risk factor for neurodegenerative disease in general, and that potentially this class of TREM2 variant carriers with dementia should be considered as having a molecularly distinct form of neurodegenerative disease
The association of TREM2 variants with AD brings innate immune signaling into the light, affirming innate immunity's role as a significant factor in AD pathogenesis
The purpose of this paper is to discuss these recent developments including the potential role that TREM2 normally plays and how loss of function may contribute to AD pathogenesis by enhancing oxidative stress and inflammation within the CNS
Even though we are more at the beginning than at the end of sAD genetics, there is some reason for optimism given the recent identification of novel risk or protective variants (such as rare TREM2 and APP mutations) showing strong statistical associations with sAD

Answer: A rare variant of the TREM2 gene, which encodes the triggering receptor encoded in myeloid cells 2 (rs75932628-T) causing a R47H substitution has been associated with both early and late onset Alzheimer's disease in various populations.  Emerging evidence has demonstrated that TREM2 could suppress inflammatory response by repression of microglia-mediated cytokine production and secretion, which may prevent inflammation-induced bystander damage of neurons. Higher levels of TREM2 mRNA (p = 0.002) and protein (p < 0.001) were identified in AD patients which indicates that TREM2 might serve as a novel noninvasive biomarker for AD diagnosis. Based on the potential protective actions of TREM2 in AD pathogenesis, targeting TREM2 might provide new opportunities for AD treatment.
Exact answer: yes