Abstract
RATIONALE: Gitelman syndrome (GS) is a rare hereditary electrolyte disorder caused by mutations in the SLC12A3 gene. There is limited literature on the role of hydrochlorothiazide (HCT) testing and the SLC12A3 single heterozygous mutation in the diagnosis and management of patients with GS. In addition, cases of GS with concomitant kidney stones are rare. PATIENT CONCERNS: A 48-year-old male patient suffered from unexplained hypokalemia for >10 years. DIAGNOSES: The patient was diagnosed with GS, type 2 diabetes mellitus, and kidney stones. INTERVENTIONS: He was given potassium chloride sustained-release tablets and potassium magnesium aspartate tablets. OUTCOMES: His irregular potassium supplementation and hypoglycemic therapy resulted in poor control of potassium and blood glucose levels. LESSONS: When unexplained hypokalemia is observed, the HCT test can help with the diagnosis of GS. When genetic testing reveals that a patient only carries only 1 SLC12A3 mutant allele, he requires further genetic evaluation. The patient's combination of kidney stones and cysts could not exclude the diagnosis of GS. Patients with GS and diabetes should be monitored for the development of diabetic ketoacidosis.