Polymorphisms in genes ACE (angiotensin-converting enzyme), APOE (apolipoprotein E), MTHFR (methylene tetrahydropholate reductase), NOS3 or ENOS (nitric oxide synthase 3 or endothelial nitric oxide synthase) and VEGF (vascular endothelial growth factor) have been shown to contribute to DPN as well as DN. The gene discussed is NOS3; the disease is liver dysplastic nodule.