BLM and Wilms tumor: A second pattern that emerged was the absence of clonal second “hits” (i.e. driver events) in recessive predisposition genes with an unclear link to Wilms tumour (NBN, PMS2, BLM (PD49219 only), BRCA2, CHEK2), consistent with the aforementioned lack of somatic mutational imprints of the underlying predisposition.