Although del(11q) has long been recognized as a marker of poor prognosis in CLL and patients carrying this chromosomal abnormality frequently present with lymphadenopathy, face a higher risk of progression, and generally have an inferior prognosis [8, 9, 11–16], there are currently conflicting data on whether mutations in ATM with or without del(11q) are indicative of a poor clinical outcome. The gene discussed is ATM; the disease is B-cell chronic lymphocytic leukemia.