PRRT1 and granular corneal dystrophy type II: Numerous studies have demonstrated the smoking impacts on the epigenetic landscape, particularly on DNA methylation across the entire genome.15, 16, 17 These methylation changes contribute to the increased risk of allergic diseases especially asthma.18, 19, 20, 21, 22 Our study identified that the CpG site cg17272563, located in the PRRT1 gene, exhibits a cross-disease effect, influencing the risk of developing asthma as well as AC and ACD.