TPSAB1 and urticaria: The urticaria risk allele of the upstream gene variant rs4410077[T], at TPSD1, positively correlates with the variant rs8051930[A] (r2 = 0.84) associating with increased plasma levels of TPSAB1 (pQTL), and higher RNA expression levels of TPSD1 (eQTL), and TPSB2 (eQTL) in blood, all at the same locus coding tryptases (Supplementary Data 11–14).