Assessing the genetic associations between plasma lipidomic profiles and psoriasis vulgaris

Several studies have indicated a potential causal relationship between plasma standard lipids, such as high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and total cholesterol (TC), and psoriasis. However, few studies have offered causal evidence of lipid species beyond these standard lipids. We conducted an analysis using a genome-wide association study (GWAS) dataset comprising 179 lipid species, including 13 types across four major categories, to identify instrumental variables (IVs) associated with plasma lipids. We utilized two GWAS datasets from the IEU and Finngen for psoriasis vulgaris as the outcome. A two-sample Mendelian randomization (MR) analysis was used to explore the causal relationship between 179 lipid species and psoriasis vulgaris in two datasets. Lipid species showing causal association in both psoriasis datasets were compared for overlap. Our study identified potential causal relationships between six lipid species and psoriasis vulgaris: phosphatidylcholine (16:1_18:2), phosphatidylcholine (18:0_18:2), phosphatidylcholine (18:1_20:4), phosphatidylethanolamine (16:0_18:2), phosphatidylinositol (18:0_20:3), and triacylglycerol (50:1). In summary, elevated plasma levels of phosphatidylcholine (16:1_18:2), phosphatidylcholine (18:0_18:2), phosphatidylethanolamine (16:0_18:2), phosphatidylinositol (18:0_20:3), and triacylglycerol (50:1) may increase the risk of psoriasis vulgaris. Conversely, plasma phosphatidylcholine (18:1_20:4) may play a protective role against psoriasis vulgaris.