Independently, the research group led by Professors Smithies and Maeda at the University of North Carolina showed that mice lacking a functional Npr1 gene, which encodes NPR-A (i.e. GC-A), have elevated blood pressure and marked cardiac hypertrophy with interstitial fibrosis, resembling that seen in human hypertensive heart disease [19]. Here, NPR1 is linked to cardiac hypertrophy.