Fibronectin was one of the first genes to be studied in terms of its ability to be alternatively spliced.29,127–130 However, only more recently, discoveries have illuminated the role of fibronectin splice isoforms in arterial wall composition and hemodynamics,131,132 cardiovascular development,133 tumor microenvironment,134,135 renal fibrosis,136 and innate immunity,137 among others. Here, FN1 is linked to renal fibrosis.