Researchers from the University of Birmingham and Cancer Research UK have identified DIAL syndrome, a novel hereditary disorder caused by DIAPH1 gene mutations that compromise DNA double-strand break repair. Published in Nature Communications, the syndrome increases susceptibility to blood cancers by disrupting B cell development and causing genomic instability. Patients also experience heightened toxicity to chemotherapy and radiotherapy, presenting challenges for personalized cancer treatment strategies and highlighting a critical DNA repair pathway.