Serine/threonine protein kinase family members WNK1 (MIM♯ 605232) and WNK4 (MIM♯ 601844) [Verissimo and Jordan, 2001; Xu et al., 2000] are involved in the development of a Mendelian form of hypertension, pseudohypoaldosteronism type II, or the Gordon syndrome [Wilson et al., 2001, 2003]. Here, WNK1 is linked to Gordon syndrome.