Resistance to hypertension and high Cl^- excretion in humans with SLC26A4 mutations

Pendrin is a membrane transporter encoded by solute carrier family26A4 (SLC26A4). Mutations in this gene are known to cause hearing loss, and recent data from animal studies indicate a link between pendrin expression and hypertension; although, this association in humans is unclear. To clarify this issue, we investigated the influence of pendrin on blood pressure by analyzing demographic and biochemical data - including blood pressure and urinary electrolyte excretion - in patients with bi-allelic SLC26A4 mutations. Systolic and diastolic blood pressure and the left ventricular hypertrophy index were lower in subjects with pendrin mutations than in controls. In addition, fractional excretion of Na⁺ and Cl^- was increased and serum renin, angiotensin I and II levels were higher in subjects with pendrin mutations as compared to controls. Thus, patients with impaired pendrin function are likely to be resistant to high blood pressure due to enhanced urinary Na⁺ /Cl^- excretion. These results suggest that pendrin may regulate blood pressure through increased urinary salt excretion.