成年III型Bartter综合征1例并文献复习华中科技大学同济医学院附属同济医院

目的：总结III型Bartter综合征的临床和生化特征以及诊断方法。方法：回顾性总结我科1例长期不明原因低钾血症患者的临床表现、生化检查和基因检测结果。结果：患者,女,41岁,低钾血症2年,无服用利尿剂和肾损害药物以及缓泻剂病史。患者主诉乏力和肢体麻木,无抽搐,血压正常。生化检查有显著低钾血症,血镁正常,尿钙正常。血气分析示代谢性碱中毒。血浆肾素活性增高。肾脏B超无钙化等异常,临床疑诊先天性失盐性肾小管病。PCR检测远曲小管上皮管腔侧钠氯离子同向转运蛋白(NCCT)基因SLC12A3全部编码区26个外显子无突变,而髓袢升支粗端和远曲小管上皮基底膜侧氯离子通道蛋白基因CLCNKB第12号外显子c.1093delC杂合突变,致编码氨基酸p.His365Thr fs 368X移码突变,这是我们发现的一个新的CLCNKB基因新的突变类型。此例最后诊断为III型Bartter综合征。结论：对于低钾血症伴代谢性碱中毒和血压正常而无特殊用药史的成年患者,诊断应考虑先天性失盐性肾小管疾病包括Gitelman和III型Bartter综合征,同时检测SLC12A3和CLCNKB基因可明确诊断。

One case of Bartter syndrome type III and literature review

Objective: To summarize the clinical and biochemical characteristics as well as diagnostic methods of Bartter syndrome type III caused by a novel CLCNKB gene mutation. Methodes: Clinical manifestations, biochemical and genetic results of a patient with persistent hypokelemia of unknown reason was retrospectively analyzed.Results: The 41years old female patient presented hypokalemia for 2 years without history of administration of antidiuretics and renal injured medication as well as laxatives. She presented with fatigue and limb numb, without tetany and hypertension. Biochemical investigation demonstrated notably hypokalemia,eucalcemia and eumagnesemia, meanwhile the 24 hours urine excretions of potassium,calcium and magnesium was in normal reference range.Blood gas analysis demonstrated metabolic alkalosis, and blood rennin activity was increased.There was no renal calcification in the kidney sonography. The patient was clinically suspected to have suffered from congenital salt-losing tubulopathies (Gitelman /Bartter syndrome), detection of all 26 exons of the coding region of SLC12A3 gene, which encodes thiazide sensitive NaCl co-transporter (NCCT) in the distal convoluted tuble ,which loss of function mutation is specific for Gitelman syndrome,found no mutation, While the renal tubule-specific chloride ion channel protein gene CLCNKB detection found a heterozygous deletion mutation of c.1093delC in the 12th exon with a resultant frame shift of translated the amino acid of p.His365Thr fs 368X.The patient was finally diagnosed as Bartter syndrome typeIII.Conclusions:For adult patients presented simutaneously with hypokalemia, metabolic alkalosis,hyperactivity of rennin and normotension without history of antidiuretics and renal injured drugs administration should congenital salt-losing tubulopathies including Gitelman syndrome and Bartter syndrome suspected,gene mutation dedection of SLC12A3 and CLCNKB can make a definite diagnosis.