Genotype, phenotype, and follow-up of Chinese patients with Gitelman′s syndrome

Abstract

Objective To analyze the characteristics of the genotype, phenotype, and follow-up of Gitelman′s syndrome(GS)in the largest group of Chinese patients. Methods Sixty seven patients with GS underwent SLC12A3 gene analysis. Clinical characteristics and biochemical findings at the first presentation as well as follow-up were reviewed. Additionally, the associations of genotypes and phenotypes were explored. Results Forty-one different SLC12A3 mutations were identified in 67 patients with GS, including 11 novel ones, and 5 recurrent ones. 3 families(5.7%)had triple SLC12A3 mutations. Typical hypocalciuria and hypomagnesemia were not found in 6(9%)and 8(11.9%)patients, respectively. In addition, male patients had an earlier age of onset and a higher urinary fraction excretion of electrolytes. 2 patients presented with chronic kidney disease, 13(19.4%)with type 2 diabetes, 14(20.9%)with impaired glucose tolerance, and 5(7.5%)with impaired fasting glucose. Conclusion This study revealed 41 mutations in 67 Chinese patients with GS, including 11 novel variants and 5 high-frequency ones. Fraction excretion of electrolyte in urine may be more sensitive in the evaluation of phenotype compared with those of blood. It is difficult to correct hypokalemia and hypomagnesemia in GS. Patients with GS are at higher risk of the development of diabetes than ordinary people. (Chin J Endocrinol Metab, 2017, 33: 40-46) Key words: Gitelman′s syndrome; Genotype; Phenotype; Follow-up; SLC12A3 gene