Colussi Giacomo, Bettinelli Alberto, Tedeschi Silvana, De Ferrari Maria Elisabetta, Syrén Marie Louise, Borsa Nicolò, Mattiello Camilla, Casari Giorgio, Bianchetti Mario Giovanni
Unité Operative Nefrologia, Ospedale di Circolo e Fondazione Macchi, Varese, Italy.
Clin J Am Soc Nephrol. 2007 May;2(3):454-60. doi: 10.2215/CJN.02950906. Epub 2007 Mar 14.
Although the diagnosis of Gitelman syndrome (GS) and Bartter syndrome (BS) is now feasible by genetic analysis, implementation of genetic testing for these disorders is still hampered by several difficulties, including large gene dimensions, lack of hot-spot mutations, heavy workup time, and costs. This study evaluated in a cohort of patients with genetically proven GS or BS diagnostic sensibility and specificity of a diuretic test with oral hydrochlorothiazide (HCT test). Forty-one patients with GS (22 adults, aged 25 to 57; 19 children-adolescents, aged 7 to 17) and seven patients with BS (five type I, two type III) were studied; three patients with "pseudo-BS" from surreptitious diuretic intake (two patients) or vomiting (one patient) were also included. HCT test consisted of the administration of 50 mg of HCT orally (1 mg/kg in children-adolescents) and measurement of the maximal diuretic-induced increase over basal in the subsequent 3 h of chloride fractional clearance. All but three patients with GS but no patients with BS and pseudo-BS showed blunted (<2.3%) response to HCT; patients with BS and the two patients with pseudo-BS from diuretic intake had increased response to HCT. No overlap existed between patients with GS and both patients with BS and pseudo-BS. The response to HCT test is blunted in patients with GS but not in patients with BS or nongenetic hypokalemia. In patients with the highly selected phenotype of normotensive hypokalemic alkalosis, abnormal HCT test allows prediction with a very high sensitivity and specificity of the Gitelman genotype and may avoid genotyping.
尽管通过基因分析现在可以对吉特曼综合征（GS）和巴特综合征（BS）进行诊断，但针对这些疾病的基因检测实施仍受到诸多困难的阻碍，包括基因规模大、缺乏热点突变、前期检查时间长以及成本高。本研究在一组经基因证实患有GS或BS的患者队列中评估了口服氢氯噻嗪利尿试验（HCT试验）的诊断敏感性和特异性。研究了41例GS患者（22例成年人，年龄25至57岁；19例儿童 - 青少年，年龄7至17岁）和7例BS患者（5例I型，2例III型）；还纳入了3例因偷偷服用利尿剂（2例患者）或呕吐（1例患者）导致“假性BS”的患者。HCT试验包括口服50毫克氢氯噻嗪（儿童 - 青少年为1毫克/千克），并在随后3小时内测量最大利尿诱导的氯分数清除率相对于基础值的增加。除3例GS患者外，所有患者以及无1例BS和假性BS患者对HCT的反应减弱（<2.3%）；BS患者以及2例因服用利尿剂导致假性BS的患者对HCT的反应增强。GS患者与BS和假性BS患者之间没有重叠。GS患者对HCT试验的反应减弱，但BS患者或非遗传性低钾血症患者则不然。在具有血压正常的低钾性碱中毒这一高度选择性表型的患者中，异常的HCT试验能够以非常高的敏感性和特异性预测吉特曼基因型，并且可能避免进行基因分型。
