Bartter 증후군과 Gitelman 증후군 = Bartter syndrome and Gitelman syndrome

다국어 초록 (Multilingual Abstract)

Bartter`s syndrome is a group of rare autosomal-recessive disorders with a unifying pathophysiology consisting of severe reductions in, or losses of, salt absorption by the thick ascending limb of Henle (TAL). The characteristic phenotype of Bartter`s syndrome is renal salt wasting, hypokalemic metabolic alkalosis, hypercalciuria with a variable risk of renal stones and elevated renin and aldosterone levels, with normal or low blood pressure. Recent advances in the field of molecular genetics have demonstrated that there are five genetically distinct abnormalities, which result from mutations in renal electrolyte transporters and channels. Previously, three genes (SLC12A1, the sodium-potassium-chloride co-transporter; KCNJ1, the ROMK potassium ion channel; ClC-Kb, the basolateral chloride ion channel) had been identified as causing antenatal and `classic` Bartter`s syndrome. Two additional genes have now been identified. Barttin is a β-subunit that is required for the trafficking of CLC-K (both ClC-Ka and ClC-Kb) channels to the plasma membrane in both the thick ascending limb and the marginal cells in the scala media of the inner ear that secrete potassium ion-rich endolymph. Loss-of-function mutations in barttin thus cause Bartter`s syndrome with sensorineural deafness. In addition, severe gain-of-function mutations in the extracellular calcium ion-sensing receptor can result in a Bartter`s phenotype because activation of this G protein-coupled receptor inhibits salt transport in the thick ascending limb. Gitelman`s syndrome shares similar clinical characteristics with Bartter`s syndrome but, is distinguished from Bartter`s syndrome by hypomagnesemia and hypocalciuria. Gitelman`s syndrome is due to mutations in the gene encoding the Na-Cl cotransporter (NCCT).