Turman M A
Department of Pediatrics, The Ohio State University and Children's Hospital, Columbus 43205, USA.
Pediatr Nephrol. 1998 Jan;12(1):23-5. doi: 10.1007/s004670050396.
The molecular defects responsible for the two most-common forms of inherited normotensive hypokalemic metabolic alkalosis have recently been defined. Most patients with Bartter syndrome have defects in transporters in the thick ascending limb of the loop of Henle, such as the Na-K-2Cl cotransporter, NKCC2, or the ATP-sensitive potassium channel, ROMK. Patients with Gitelman syndrome usually have mutations in the thiazide-sensitive Na-Cl cotransporter in the distal convoluted tubule. The location of the affected transporters correlates well with the typical presentation of these syndromes. Patients with Bartter syndrome typically present with normal or increased calcium excretion. Hypomagnesemia is present in only one-third of affected individuals. In contrast, hypomagnesemia and hypocalciuria are considered hallmarks of Gitelman syndrome. This report describes siblings presenting as young adults with mild symptoms associated with normotensive hypokalemic metabolic alkalosis. One sibling has hypocalciuria and hypomagnesemia, consistent with Gitelman syndrome. Surprisingly, the other sibling has normal serum magnesium and urinary calcium excretion. These siblings demonstrate the biochemical heterogeneity that can exist in patients with normotensive hypokalemic metabolic alkalosis. This report indicates that hypocalciuria does not always distinguish Gitelman and Bartter syndromes.
导致两种最常见的遗传性正常血压性低钾血症性代谢性碱中毒的分子缺陷最近已被明确。大多数巴特综合征患者在髓袢升支粗段的转运体存在缺陷，如钠-钾-2氯协同转运蛋白（NKCC2）或ATP敏感性钾通道（ROMK）。吉特林综合征患者通常在远曲小管的噻嗪类敏感钠-氯协同转运蛋白存在突变。受影响转运体的位置与这些综合征的典型表现密切相关。巴特综合征患者通常表现为钙排泄正常或增加。只有三分之一的受影响个体存在低镁血症。相比之下，低镁血症和低钙尿症被认为是吉特林综合征的标志。本报告描述了一些成年后出现与正常血压性低钾血症性代谢性碱中毒相关的轻度症状的兄弟姐妹。其中一个兄弟姐妹有低钙尿症和低镁血症，符合吉特林综合征。令人惊讶的是，另一个兄弟姐妹的血清镁和尿钙排泄正常。这些兄弟姐妹展示了正常血压性低钾血症性代谢性碱中毒患者可能存在的生化异质性。本报告表明，低钙尿症并不总是能区分吉特林综合征和巴特综合征。
