Gitelman syndrome (GS) is a hereditary renal tubulopathy caused by mutations in the SLC12A3 gene which encodes the thiazide-sensitive apical sodium-chloride cotransporter. GS is characterized by hypokalaemia, hypomagnesaemia and metabolic alkalosis. Treatment is based on potassium and magnesium replacement ad eternum. We present the case of a young man with palpitations and persistent hypokalaemia, who was diagnosed with GS. Genetic testing revealed 2 mutations in the gene SLC12A3 of combined heterozygosity, both considered pathological. Interestingly, 1 of these mutations was not yet described in the literature or in the reviewed databases. We also discuss the clinical approach and the specificities of managing this rare hereditary renal tubulopathy.