Representative examples of somatic SAMHD1 mutations. (A) Electropherogram of SAMHD1 mutations using paired germ-line and tumor DNA. (Upper) Representative results from 2 patients are depicted. (Lower) Whole genome arrays showing (left) copy neutral loss of heterozygosity (cnLOH) or (right) a heterozygous deletion over chromosome 20 involving the SAMHD1 locus. (B) Multiple sequence alignment of SAMHD1 around the mutated residue (arrow) of each patient. Degree of conservation is reflected by background color code (dark blue, highly conserved to white, not conserved). (C) Whole genome array showing a small homozygous deletion at the 5′ end of the SAMHD1 locus in patient CLL 095.