To investigate the clinical characteristics and genetic variations of Gitelman syndrome (GS).

A case of GS diagnosed in November 2024 at Xi′an Children′s Hospital (patient 1) was included in the study. Clinical data, whole-exome sequencing (WES) results, and sanger sequencing validation results of patient 1 were retrospectively collected. Variants identified were classified for pathogenicity according to the Standards and Guidelines for the Interpretation of Sequence Variants by the American College of Medical Genetics and Genomics (ACMG). Literature on pediatric GS cases confirmed to be caused by SLC12A3 gene mutations was retrieved from the China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Chinese Science and Technology Journal Database, and PubMed, using the Chinese and English keywords " Gitelman syndrome" and " SLC12A3". The literature search period was set from January 1, 2022, to March 31, 2025. The procedures of this study complied with the regulations of the Ethics Committee of Xi′an Children′s Hospital and were approved by the committee (Approval No.20240133). Informed consent was obtained from the guardian of patient 1.

①The patient is a 6-year-and-6-month-old boy who admitted to case collected hospital with " intermittent vomiting for two week." The results of relevant auxiliary examinations at admission showed low serum K⁺ concentration which was 1.64 mmol/L and low serum Cl^- concentration which was 89.7 mmol/L while serum Mg²⁺, Ca²⁺, and Na⁺ concentrations were normal. Despite repeated potassium supplementation, the therapeutic response was poor. The etiology of hypokalemia remained unclear, suggesting the possibility of an underlying genetic disorder. His result of genetic testing showed SLC12A3 gene compound heterozygous mutations: c. 1956delC(p.Asn653Thrfs*19) and c. 2029G>A(p.Val677Met), inherited from his father and mother, respectively. Based on his clinical manifestations and genetic testing results, he was diagnosed as GS. After oral treatment by potassium chloride and spironolactone, the patient 1 showed no recurrence of vomiting symptoms upon follow-up until May 2025, with serum electrolyte levels remaining within normal ranges. ②Literature review results: a total of 20 pieces of relevant research literature involving 24 cases of GS children caused by SLC12A3 gene mutations were retrieved. Among them, 7 cases exhibited growth retardation, and 3 cases primarily presented with vomiting symptoms at onset. All patients demonstrated hypokalemia. Six cases showed normal serum magnesium levels, while the remaining patients exhibited varying degrees of hypochloremic alkalosis, hypophosphatemia, hypocalciuria, and elevated renin-angiotensin-aldosterone system activity.

Childhood GS has an atypical clinical presentation in childhood. The presence of refractory hypokalemia and metabolic alkalosis warrants high clinical suspicion, and prompt genetic confirmation is critical for diagnosis and treatment.