To date, there have been several linkage studies to identify genetic loci determining renal function in individuals with renal disease or in the normal population. Puppala et al. suggested candidate regions including 2q36.3 and 9q21.31–q21.33 in the Mexican–American population, and Schelling et al. reported the 1q43, 7q36.1, 8q13.3, and 18q23.3 regions using multiethnic diabetic populations. There are several additional regions that have been suggested from other linkage studies, including 7p15.3–p13, 12p12.2, and 16q12.2–16q23.1. In recent years, researchers have tried to determine in more detail the genetic basis of the estimated GFR (eGFR) through genome-wide association studies (GWAS), and have begun suggesting some genes or variants as determinants of eGFR or chronic kidney disease. These studies, based on a large number of samples, have identified several variants showing a high level of significance and reproducibility near or within genes including UMOD, SHROOM3, GATM, and SPATA5L1.