REN and essential hypertension: Worapaka Manosroi et al. categorized primary hypertension into four tiered subgroups in a recent review: (a) distant phenotype (hypertension), (b) intermediate phenotype (salt-sensitive and salt-resistant hypertension), (c) subintermediate phenotypes within salt-sensitive hypertension (normal renin and low renin), and (d) proximate phenotypes (genotype-specific hypertensive subgroup).