MECOM mutations in patients with congenital BMF and consequences for protein isoforms of MECOM. Exon structure of the MECOM locus together with the main transcript variants are shown together with constitutive mutations in MECOM found in this study. The transcript variants use different start codons and alternatively spliced amino termini. Truncating mutations are labeled in red, missense mutations in blue, and 5′ untranslated region mutations in black. Patient identifiers for those affected by RUSAT are labeled in green. Pathogenic mutations (P1-P12) are labeled in full color; mutations of uncertain significance of pathogenicity or benign variations (P13-P20) are labeled in pale colors. Diamonds indicate nonsense mutations; triangles indicate frameshift mutations. AD, acidic domain; NLS, nuclear localization sequence; RD, repression domain; S, splice site mutation; ZF, zinc finger motif.