The chromosome 11p15.5 region that is altered in individuals with BWSp harbours several imprinted genes, among them CDKN1C, IGF2 and H19, which are regulators of growth.24 Therefore, the observed high cancer risk in individuals with BWSp who carry a constitutional or mosaic lesion in the 11p15.5 region is biologically plausible. The gene discussed is H19; the disease is cancer.