With the advent of radioimmunoassays for PTH (Brewer and Ronan, 1970; Niall et al., 1970; Llach et al., 2000), high circulating levels of PTH were detected at earlier stages of CKD (Llach et al., 2000); however, it was not until 1970 that characterization of the PTH molecule was completed, which helped to its cloning in 1983 (Brewer and Ronan, 1970; Niall et al., 1970; Vasicek et al., 1983). This evidence concerns the gene PTH and chronic kidney disease.