Key functional domains of NBN are preferentially affected by genetic variation. (A) The top panel summarizes the frequency in B-ALL cases, effects on MMC drug sensitivity, and NBN protein stability for each NBN variant. The bottom panel depicts the alignment of NBN protein sequences from human (Homo sapiens; NP_002476.2), mouse (Mus musculus, NP_038780.3), rat (Rattus norvegicus; NP_620228.1), and monkey (Macaca mulatta; NP_001252668.1). Protein sequence alignment was done in COBALT NCBI Multiple Sequence Alignment Viewer, version 1.22.0. (B) AlphaFold structure prediction of NIBRIN (AF-O60934-F1): FAH domain in orange, BRCT I and II in red, and C-terminal domain in green. Experimentally validated functional NBN variants relate to the peripheral moieties, whereas nonfunctional and partially functional NBN variants relate to the NBN central region. (C) Cumulative burden of putatively damaging NBN variants in B-ALL cases vs gnomAD noncancer controls calculated by ancestry-based stratified analysis using the Cochran-Mantel-Haenszel test. ∗P < .05 and ∗∗P < .01.