163 Integrative Genomics Analysis Implicates Decreased FGD6 Expression Underlying Risk of Intracranial Aneurysm Rupture

Abstract

INTRODUCTION: The genetic determinants of intracranial aneurysm rupture (rIA) are largely unknown. To identify and characterize genetic risk factors for rIA, we perform a genome-wide association study (GWAS) containing 84,353 individuals (7,843 rIA cases and 76,510 controls). We then use functional genomics approaches to delineate the mechanistic consequences of rIA risk loci. METHODS: We perform a meta-analysis across 24 published GWAS of rIA. Logistic regression was used to identify rIA-associated single nucleotide polymorphisms (SNPs). Gene-burden, expression quantitative trait loci (eQTL) mapping, and analysis of publicly-available single-cell RNA sequencing (scRNA-seq) data from normal human brain endothelial and perivascular cells was used to delineate cell-lineage expression of rIA-associated genes. RESULTS: We identify 5 independent genetic loci reaching genome-wide significance (p < 5.0 x 10-8) for rIA: rs73392700 (CDKN2B, OR = 1.12), rs6841581 (EDNRA, OR = 0.77), rs11661542 (RBBP8, OR=0.84), rs62516550 (RP1, OR = 1.20), and rs12310399 (FGD6, OR = 1.16). FGD6, to our knowledge, has not been implicated in prior GWAS of (r)IA. We then quantified gene-level mutation-burden across ∼20,000 genes, and only FGD6 (containing 21 rIA-associated SNPs) reached transcriptome-wide significance. Functional eQTL mapping indicates that rs12310399 causes decreased FGD6 gene expression in arterial tissue. scRNA-seq identified high expression of FGD6 in 1 of 3 arterial lineages, but absent in perivascular cells, identifying the likely cell-lineage underlying FGD6-mediated rIA risk. CONCLUSIONS: We perform the largest genetic study of rIA to date. We identify and characterize a previously unknown risk loci for rIA containing FGD6. Elucidation of high-risk genetic loci may instruct population-genetic screening and clinical-genetic testing strategies to identify patients predisposed to rIA enabling early treatment and improved patient outcomes.