Serum (sodium, potassium, creatinine and renal function, haemoglobin, fasting glucose, HbA1c, fasting lipids, thyroid-stimulating hormone, renin and aldosterone) and urine (sodium, potassium, creatinine, protein and (micro-)albumin) laboratory testing will have to be performed to assess renal function, to evaluate existing HMOD, if any, and to detect potential secondary causes for hypertension. This evidence concerns the gene REN and hypertensive disorder.