ATP1A1 and Hypertension: The α1 Na,K-ATPase (ATP1A1) is the sole active Na+ transporter in the renal basolateral epithelia throughout the nephron [4–6] and in vascular endothelium [7], and given the role of sodium as a major risk factor for hypertension, the ATPA1 gene is a logical candidate gene for susceptibility to salt-sensitive ‘essential’ or polygenic hypertension [4–6].