目的　探讨先天性失氯性腹泻(CCD)的临床诊治及基因诊断。方法　回顾性分析1例表现为持续腹泻、低氯血症、低钠血症、低钾血症和代谢性碱中毒的男性、1月龄患儿的大便电解质检测、临床治疗随访以及患儿及其父母SLC26A3基因突变分析的资料。结果　患儿大便电解质Cl-、K+明显升高，Cl- >Na+和K+之和；经氯化钠和氯化钾替代治疗，血电解质恢复正常。随访4年，患儿生长发育尚可。患儿为SLC26A3基因c.239G>A(p.Gly80Asp纯合突变，父母该位点均为相同的杂合突变，该突变首次在国内发现。结论　SLC26A3基因分析有助于CCD的诊断。

　Objective　To discuss the clinical diagnosis, treatment and genetic diagnosis of congenital chloride diarrhea (CCD), a rare autosomal recessive disease. Methods One month old boy with persistent diarrhea, hypochloremia, hyponatremia, hypokalemia and metabolic alkalosis, his stool electrolyte testing, clinical treatment and follow-up, as well as his and his parents’ SLC26A3 gene mutation analysis were retrospectively analyzed. Results The fecal electrolyte testing showed that the levels of Cl- and K+ were increased and the level of Cl- was much higher than the sum of Na+ and K+. After replacement therapy with NaCl and KCl, the blood electrolyte recovered to normal. Follow-up 4 years, the boy had a normal growth and development. Mutation analysis on SLC26A3 gene showed there was a homozygous mutation of 239G>A and both his father and mother carried the same heterozygous mutation. This mutation was first discovered in China. Conclusions The sequencing analysis of SLC26A3 mutation may help to diagnosis CCD.