A Case of Gitelman Syndrome Complicated by Growth Hormone Deficiency.

Background: In September 2022, a case of Gitelman syndrome combined with growth hormone deficiency was diagnosed in the pediatrics department of our hospital. The patient was a 14-year-old male who was admitted to the hospital due to weakness in both lower extremities for two days and the symptoms had worsened within half a day. From 2016 to 2022, the patient had been hospitalized four times for hypokalemia. The clinical manifestations included weakness in both lower extremities, difficulty walking, muscle pain in the lower extremities and thirst.

Methods: Blood and urine electrolyte tests, genetic testing for hereditary kidney diseases, and growth hormone stimulation tests were conducted.

Results: Laboratory test results showed potassium (K+) at 1.90 mmol/L, magnesium (Mg) at 0.65 mmol/L, 24-hour urine calcium at 0.12 mmol/24 hour, pH at 7.454, PaCO2 at 44.5 mmHg, PaO2 at 90 mmHg, HCO3- at 31.2 mmol/L, and BE at 7 mmol/L. Genetic testing for hereditary kidney diseases revealed that the child and his mother carried a heterozygous nucleotide variation of the SLC12A3 gene, c.497C>T, resulting in a missense variation of p.Ala166Val; the father did not have this variation, and no large fragment variations of the SLC12A3 gene were found. The final diagnosis was Gitelman syndrome caused by a single heterozygous mutation. Additionally, the patient's height was 148 cm (below the third percentile, -2.49 SD), and the results of the growth hormone stimulation test indicated growth hormone deficiency. After a multidisciplinary consultation, the diagnosis was con-firmed as: 1. Gitelman syndrome (hypokalemia); 2. Growth hormone deficiency. Oral spironolactone tablets were given for potassium retention treatment, and subcutaneous injection of recombinant human growth hormone was recommended. The patient's condition improved, and regular follow-ups were advised.

Conclusions: Case of Gitelman syndrome (GS) combined with growth hormone (GH) deficiency are relatively rare. This case enriches the understanding of concurrent symptoms of GS and is helpful for improving the clinical understanding and treatment level of this disease.