Schematic of RUNX1 exonic distribution, protein isoforms, and functional domain structure with all 52 pilot variants and their final MM-VCEP classification. (A) Isoform C with RHD, transactivation domain (TAD), and the VWRPY motif and location of all 49 single-nucleotide pilot variants with their final MM-VCEP classification. PATH and LPATH variants are shown at the top, and VUS, LBEN, and BEN variants are shown at the bottom. The exonic distribution of isoform C is displayed below. (B) Schematic of RUNX1 isoforms A, B, and C and their functional domains. Regions in gray are unique to 1 isoform. The 3 pilot CNVs are shown at the bottom, with the deletion of exons 2 and 3 exclusively affecting the N-terminal 33 AA of isoform C.