Laboratory examinations including urine free normetanephrine (NMN) and metanephrine (MN) were all normal (NMN 185μg/24h, normal range 28-615μg/24h; MN 149μg/24h, normal range 14-282 μg/24h) except for hypokalemia (3.12 mmol/L, normal range 3.5–5.3 mmol/L) and a slightly elevated plasma renin concentration (66.1 μIU/mL, normal range 4.4–46.1 μIU/mL), ruling out the possibility of pheochromocytoma. Here, REN is linked to hereditary pheochromocytoma-paraganglioma.