Predicted schematic representation of the WBS-CNV2 deletion and duplication variants and mechanisms of generation. Based on the known architecture of the WBS locus, inversions between the medial and telomeric blocks of LCRs are likely to occur. In fact, such inversions are already present in the regional maps obtained by different assemblies of the human genome (Hillier et al. 2003; Scherer et al. 2003). Chromosomes with such inversion types would present two blocks of the medial and telomeric LCRs, A or B, depending on the inversion breakpoint, arranged in tandem with the other block between. This structure might facilitate the generation of deletions and duplication of only two blocks (excluding block C) by NAHR between the blocks in tandem, consistent with the WBS-CNV2 variants found.
