Department of Endocrinology, Skane University Hospital, Lund, Sweden
Department of Endocrinology, Skane University Hospital, Lund, Sweden.
BMJ Case Rep. 2023 Feb 9;16(2):e254274. doi: 10.1136/bcr-2022-254274.
A young man presented unconscious with severe hyponatraemia, hypokalaemia, hypomagnesaemia and metabolic alkalosis. After 4 months of treatment in hospital, the hypomagnesaemia persisted. The patient had no signs of diabetes mellitus, and radiology showed no abnormalities of the kidneys, pancreas or genitourinary tract. A parenteral magnesium load demonstrated renal wasting with increased fractional urinary excretion of magnesium. Genetic tests for Gitelman as well as Bartter syndromes were negative. However, a wider genetic panel revealed that the patient was heterozygous for a deletion on chromosome band 17q12, encompassing the whole HNF1B gene.This case highlights the importance of considering pathogenic HNF1B variants in isolated profound hypomagnesaemia caused by renal wasting. Pathogenic HNF1B variants may partly mimic hypomagnesaemia found in Gitelman and Bartter syndromes and may be present without other features linked to HNF1B variants, including diabetes mellitus.
一名年轻男子无意识就诊，伴有严重低钠血症、低钾血症、低镁血症和代谢性碱中毒。住院治疗 4 个月后，低镁血症仍持续存在。该患者无糖尿病的迹象，影像学检查显示肾脏、胰腺或泌尿生殖道均无异常。静脉注射镁负荷试验显示肾脏镁排泄增加，尿镁排泄分数增加。进行 Gitelman 综合征和 Bartter 综合征的基因检测均为阴性。然而，更广泛的基因检测发现，患者 17q12 染色体带的杂合性缺失，涵盖整个 HNF1B 基因。本病例强调了在由肾脏排泌导致的孤立性严重低镁血症中，考虑致病性 HNF1B 变异的重要性。致病性 HNF1B 变异可能部分模拟 Gitelman 综合征和 Bartter 综合征中的低镁血症，且可能在无其他与 HNF1B 变异相关特征的情况下存在，包括糖尿病。
