Analysis of leukemia-prone polymorphic alleles (XPA A23G, XPD Lys751Gln, XRCC1 Arg399Gln, XRCC3 Thr241Met, and RAD51 G135C) revealed an XPD and XRCC3-deficient heterozygous pre-SCT patient with normal alleles for XPA, XRCC1, and RAD51 DNA repair functions (Table 2 and Figure 3). Here, ERCC2 is linked to leukemia.