Genetic analysis of the PCSK9 locus in psychological, psychiatric, metabolic and cardiovascular traits in UK Biobank.

Abstract

The association between severe mental illness (SMI) and cardiovascular and metabolic disease (CMD) is poorly understood. PCSK9 is expressed in systems critical to both SMI and CMD and influences lipid homeostasis and brain function. We systematically investigated relationships between genetic variation within the PCSK9 locus and risk for both CMD and SMI. UK Biobank recruited ~500,000 volunteers and assessed a wide range of SMI and CMD phenotypes. Initially we used genetic data from white British ancestry individuals of UK Biobank. Genetic association analyses were conducted in PLINK, with statistical significance defined by the number of independent SNPs. Conditional analyses and linkage disequilibrium assessed the independence of SNPs and the presence of multiple signals. Two genetic risk scores of lipid-lowering alleles were calculated and used as proxies for putative lipid-lowering effects of PCSK9. PCSK9 variants were associated with central adiposity, venous thrombosis embolism, systolic blood pressure, mood instability, and neuroticism (all p<1.16x10-4). No secondary signals were identified. Conditional analyses and high linkage disequilibrium (r2 =0.98) indicated that mood instability and central obesity may share a genetic signal, which was confirmed using trans-ancestry data from UK Biobank. Genetic risk scores suggested that the lipid-lowering effects of PCSK9 may be causal for greater mood instability and higher neuroticism. This is the first study to implicate the PCSK9 locus in mood-disorder symptoms and related traits, as well as the shared pathology of SMI and CMD. PCSK9 effects on mood may occur via lipid-lowering mechanisms. Further work is needed to understand whether repurposing PCSK9-targeting therapies might improve SMI symptoms and prevent CMD.

PCSK9 deficiency alters brain lipid composition without affecting brain development and function

“…Moreover, recent studies indicate that PCSK9 protein levels are inreased in Alzheimer's disease (AD; Zimetti et al, 2016;Picard et al, 2019), and positively correlated with depression score (Macchi et al, 2020). Furthermore, PCSK9 genetic variants were found to be associated with greater mood instability and higher neuroticism in the UK Biobank (Hay et al, 2022).…”