CEBPA mutations, CCG-2941/2961 and COG-AAML03P1. (A) Fragment-length analysis, showing representative mutations. NTD: (i) wild type; (ii) 1-bp deletion; (iii) 4-bp insertion. bZip: (iv) wild type; (v) 6-bp insertion; (vi) 24-bp insertion. (B) Location of each functional mutation. Mutations that are one of a pair of CEBPA mutations within the same patient, or “double” mutations, are depicted in red. Polymorphisms are not shown. (C) Thirty-one patients (82% of those with mutations) harbored “double” mutations, pairing an N-terminal truncating mutation with an in-frame bZip mutation. Of the patients with “single” mutations, only one patient had an NTD mutation alone.