SMARCB1 and Coffin-Siris syndrome: Regarding germline and somatic KMT2D variants non-mutually exclusive parallels can be drawn with the situation for ARID1A/B- and SMARCB1. E.g. for ARID1A/B truncating germline variants cause Coffin-Siris-Syndrome but may not predispose to cancer although truncating somatic variants are frequently present in cancer [136, 137].