First European case of Geller syndrome complicated with hypokalemic nephropathy: A case report and literature review.

Geller syndrome is caused by a gain-of-function mutation in the mineralocorticoid receptor (MR), rendering it prone to activation by elevated progesterone levels during pregnancy. It is characterized by gestational hypertension and hypokalemia. We describe the case of a 35-year-old primigravida, who presented at 22 weeks of gestation with severe hypokalemia and hypertension, complicated by hypokalemic nephropathy manifesting as diabetes insipidus and proteinuria. Initial potassium replacement, eplerenone administration and desmopressin were insufficient, whereas the administration of amiloride, a potassium-sparing diuretic that inhibits epithelial sodium channels (ENaC) in the distal nephron, led to complete resolution of the clinical syndrome. The patient had no further complications and delivered a healthy infant at 37 weeks. Genetic testing did not reveal known MR mutations, suggesting that other genetic variants or epigenetic changes in MR may warrant future investigation, particularly in isolated populations. To date, 17 cases of Geller syndrome have been reported in the literature including the herein presented, which is to the best of our knowledge the first documented in Europe. Genetic testing was performed in only one case, apart from the initially reported ones. Urgent delivery was required in four cases, while amiloride, the treatment of choice, was administered in only five, highlighting the importance of early recognition of the syndrome for effective management and prevention of adverse pregnancy outcomes.