Adult-Onset Gitelman Syndrome: Case Analysis and Literature Review.

Background: Gitelman syndrome is a rare autosomal recessive renal tubulopathy, characterized by hypomagnesemia, hypokalemia, hypochloremia, and metabolic alkalosis. The syndrome commonly presents with symptoms such as fatigue, muscle cramps, and tetany, impacting patients' quality of life. Although genetic confirmation via identification of mutations in the SLC12A3 gene is ideal, resource constraints often limit access to these tests, especially in low-resource settings. This study aims to analyze the clinical, biochemical, and familial features of Gitelman syndrome in three patients, highlighting the syndrome's characteristic biochemical abnormalities and discussing the implications of limited genetic testing. Methods: We conducted a comparative analysis of three diagnosed cases of Gitelman syndrome. Clinical presentations, biochemical data (with emphasis on magnesium and potassium levels), and family histories were systematically collected. Due to logistical limitations, genetic testing could not be performed. A comparative evaluation was then undertaken to assess commonalities and differences among the cases. Results: All three patients presented with hallmark clinical features of Gitelman syndrome, including fatigue, muscle cramps, and intermittent tetany. Biochemical evaluation revealed persistent hypokalemia (serum potassium: 1.0-3.1 mmol/L), hypomagnesemia (0.53-0.60 mmol/L), and metabolic alkalosis (HCO₃ ^-: 28-31.5 mmol/L; pH: 7.40-7.45). Urinary electrolyte profiles demonstrated inappropriate renal losses of potassium (54 mmol/24 h), chloride (180-190 mmol/24 h), and sodium (70-120 mmol/24 h). Serum creatinine levels remained within normal limits (7-9.1 mg/L), and parathormone concentrations ranged from 30 to 32 pg/mL. No suggestive clinical signs of Bartter syndrome were observed, and secondary causes such as diuretic use, autoimmune nephropathies, and endocrinopathies were excluded. Family history was negative in two of the three cases, suggesting the potential for de novo mutations or undetected autosomal recessive inheritance. All patients were managed with oral potassium and magnesium supplementation, resulting in notable clinical and biochemical improvement, with follow-up serum potassium ranging from 3.5 to 3.9 mmol/L and magnesium from 0.74 to 1.3 mmol/L. Conclusion: The clinical and biochemical findings in these patients are strongly indicative of Gitelman syndrome, even in the absence of genetic confirmation. This study emphasizes the necessity of a multidisciplinary approach in diagnosing and managing Gitelman syndrome, where biochemical assessments and clinical findings are instrumental. While genetic testing could provide conclusive evidence, effective management through electrolyte supplementation plays a crucial role in improving patients' quality of life.