Finerenone as a Novel Treatment for Gitelman Syndrome: A Case Study of a 35-Year-Old Male with Adrenal Mass and Hypokalemia.

BACKGROUND Gitelman syndrome (GS) is an autosomal recessive salt-losing tubulopathy characterized by renal potassium loss, hypokalemia, metabolic alkalosis, hypocalciuria, hypomagnesemia, and hyper-reninemic hyperaldosteronism. Finerenone is a non-steroidal mineralocorticoid receptor antagonist that inhibits receptor-mediated sodium reabsorption and decreases receptor overactivation. This report describes a 35-year-old man with hypokalemia, a mass in the right adrenal gland, and a diagnosis of Gitelman syndrome with a c.1456>A heterozygous variant of the SLC12A3 gene, treated with finerenone. CASE REPORT A 35-year-old man was admitted to the affiliated Hospital of Qingdao University because of a mass in the right adrenal gland. He was in generally good condition upon admission. He was a non-smoker and non-drinker. The examination at admission led to diagnosis of severe hypokalemia. Genetic tests showed that he carried a homozygous pathogenic variant c.1456>A in SLC12A3, which can confirm the diagnosis of Gitelman syndrome. Spironolactone was used to increase the blood potassium level, but after adverse effects were noted, finerenone was used, which greatly improved his blood potassium levels. CONCLUSIONS For patients with Gitelman syndrome who cannot tolerate adverse effects such as sex hormone-related adverse reactions from using non-selective mineralocorticoid receptor antagonists, especially male patients, finerenone may be considered as an adjunct therapy for potassium retention and magnesium supplementation. To the best of our knowledge, this is the first report in the world of using finerenone to treat Gitelman syndrome. This provides more options for treatment of patients in the future.