Figure 2.

Mechanisms of ATM structural alterations in CLL. Upper panel: most CLL patients carry normal (represented by blue boxes in the figure) ATM genes in their germline DNA (A), although some cases may harbor germline mutations of ATM (represented by red boxes in the figure) (B). Lower panel: at some stage during the clinical history of the disease, CLL cells may acquire somatic alterations of ATM, alternatively constituted by: ATM deletion in the presence of a residual normal ATM allele (C); somatically acquired ATM mutations (represented by orange boxes in the figure) in the presence of a residual normal ATM allele (D); biallelic ATM inactivation through deletion of one allele and somatic mutation (represented by orange boxes in the figure) of the residual allele (E); biallelic ATM inactivation through somatically acquired deletion of one allele and germline mutation (represented by red boxes in the figure) of the other allele (G). In some cases, only a germline ATM mutation (represented by red boxes in the figure) is detected in CLL cells (F).