Investigating Potential Causal Relationships Between Plasma Protein Ratios and Alopecia Areata: A Bidirectional Mendelian Randomization Study

This study investigated the causal relationships between plasma protein ratios (PPRs) and alopecia areata (AA) using data from over 54,000 individuals in the UK Biobank and 862 cases with 432,686 controls from FinnGen. The analysis identified that elevated ratios of agrin (AGRN)/heparan sulfate proteoglycan 2 (HSPG2) and 2,4-dienoyl-CoA reductase 1 (DECR1)/FK506-binding protein 1B (FKBP1B) are significantly associated with an increased risk of AA. Specifically, a one standard deviation increase in the AGRN/HSPG2 ratio raises the risk of AA by 44.8%, and a similar increase in the DECR1/FKBP1B ratio raises the risk by 65.8%. Reverse analysis showed no significant causal effect of AA on these PPRs. The findings provide new insights into the diagnosis and treatment of AA.