R47H TREM2 variant increases risk of typical early-onset Alzheimer's disease but not of prion or frontotemporal dementia.
;
Rita J Guerreiro;
James B Rowe;
Claudia Ponto;
Inga Zerr;
Hans Kretzschmar;
Pierluigi Gambetti;
Sebastian J Crutch;
Jason D Warren;
Martin N Rossor;
Nick C Fox;
John Collinge;
Jonathan M Schott;
Simon Mead;
(2014)
R47H TREM2 variant increases risk of typical early-onset Alzheimer's disease but not of prion or frontotemporal dementia.
Alzheimer's & dementia, 10 (6).
602-608.e4.
ISSN 1552-5260
DOI: 10.1016/j.jalz.2014.05.1751
BACKGROUND: Rare TREM2 variants are significant risk factors for Alzheimer's disease (AD). METHODS: We used next generation sequencing of the whole gene (n = 700), exon 2 Sanger sequencing (n = 2634), p.R47H genotyping (n = 3518), and genome wide association study imputation (n = 13,048) to determine whether TREM2 variants are risk factors or phenotypic modifiers in patients with AD (n = 1002), frontotemporal dementia (n = 358), sporadic (n = 2500), and variant (n = 115) Creutzfeldt-Jakob disease (CJD). RESULTS: We confirm only p.R47H as a risk factor for AD (odds ratio or OR = 2.19; 95% confidence interval or CI = 1.04-4.51; P = .03). p.R47H does not significantly alter risk for frontotemporal dementia (OR = 0.81), variant or sporadic CJD (OR = 1.06 95%CI = 0.66-1.69) in our cohorts. Individuals with p.R47H associated AD (n = 12) had significantly earlier symptom onset than individuals with no TREM2 variants (n = 551) (55.2 years vs. 61.7 years, P = .02). We note that heterozygous p.R47H AD is memory led and otherwise indistinguishable from "typical" sporadic AD. CONCLUSION: We find p.R47H is a risk factor for AD, but not frontotemporal dementia or prion disease.