ATP2B4 and systemic mastocytosis: Individuals carrying both the GG risk genotype at rs11240391 and the ATP2B4 risk haplotype (major haplotype) had a higher risk of developing SM with 21% and 8% in SM and Ctrl, respectively (OR = 3.05, p < 0.0001) (Figures 6F and S1; Table S2), suggesting an epistatic interaction between them.