PRRT2 and cold urticaria: The role of BANK1 in the activation of RASGRP3 has not been established but could be a mechanistic link between BANK1 and BLK and the coupling between the BCR and the PKC and Ras pathways [42], [43].Recently, human dominant inherited deletions affecting the PLCg2 locus linked to cold urticaria and autoimmunity were reported [19].