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Genetic variation across RNA metabolism and cell death gene networks is implicated in the semantic variant of primary progressive aphasia.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Bonham, Luke W 
Steele, Natasha ZR 
Karch, Celeste M 
Broce, Iris 
Geier, Ethan G 

Abstract

The semantic variant of primary progressive aphasia (svPPA) is a clinical syndrome characterized by neurodegeneration and progressive loss of semantic knowledge. Unlike many other forms of frontotemporal lobar degeneration (FTLD), svPPA has a highly consistent underlying pathology composed of TDP-43 (a regulator of RNA and DNA transcription metabolism). Previous genetic studies of svPPA are limited by small sample sizes and a paucity of common risk variants. Despite this, svPPA's relatively homogenous clinicopathologic phenotype makes it an ideal investigative model to examine genetic processes that may drive neurodegenerative disease. In this study, we used GWAS metadata, tissue samples from pathologically confirmed frontotemporal lobar degeneration, and in silico techniques to identify and characterize protein interaction networks associated with svPPA risk. We identified 64 svPPA risk genes that interact at the protein level. The protein pathways represented in this svPPA gene network are critical regulators of RNA metabolism and cell death, such as SMAD proteins and NOTCH1. Many of the genes in this network are involved in TDP-43 metabolism. Contrary to the conventional notion that svPPA is a clinical syndrome with few genetic risk factors, our analyses show that svPPA risk is complex and polygenic in nature. Risk for svPPA is likely driven by multiple common variants in genes interacting with TDP-43, along with cell death,x` working in combination to promote neurodegeneration.

Description

Keywords

Apoptosis, Cohort Studies, DNA-Binding Proteins, Databases, Genetic, Gene Expression Regulation, Gene Regulatory Networks, Genome-Wide Association Study, Humans, Polymorphism, Single Nucleotide, Primary Progressive Nonfluent Aphasia, Protein Interaction Maps, RNA, Risk Factors, Transcription, Genetic

Journal Title

Scientific Reports

Conference Name

Journal ISSN

2045-2322
2045-2322

Volume Title

9

Publisher

Nature Publishing Group
Sponsorship
Wellcome Trust (103838/Z/14/Z)
Medical Research Council (MR/N026004/1)
Medical Research Council (G0301152)
Primary support for data analyses was provided by the Radiological Society of North America (RSNA) RMS1741 (LWB), Larry L. Hillblom Foundation 2016-A-005-SUP (JSY), AFTD Susan Marcus Memorial Fund Clinical Research Grant (JSY), NIA K01 AG049152 (JSY), Bluefield Project to Cure FTD (JSY), Tau Consortium (JSY), NIA K01 AG046374 (CMK), U24DA041123 (RSD), National Alzheimer’s Coordinating Center (NACC) Junior Investigator Award (RSD), RSNA Resident/Fellow Grant (RSD), Foundation of ASNR Alzheimer’s Imaging Grant (RSD), and Alzheimer’s Society Grant 284 (RF). Additional support was provided by an MRC Programme grant (MR/N026004/1; JH and PAL) and a MRC New Investigator Research Grant (MR/L010933/1; PAL). PAL is a Parkinson’s UK research fellow (grant F1002).