| ObjectiveTo systemically evaluate the features of bone metabolism and bone quality in patients with Gitelman syndrome ragarding bone metabolic markers as well as bone mineral density(BMD)and microarchitecture parameters assessed by high-resolution peripheral quantitative computed tomography(HR-pQCT).To preliminarily analyze the relationships between bone phenotypes and clinical phenotypes and that between bone phenotypes and mutation types of GS patients.MethodsThe study was conducted with a cross-sectional design,including 27 patients diagnosed with GS in the Department of Endocrinology of Peking Union Medical College Hospital from 2017-2019.Information on clinical history,biochemical indexes and bone metabolic marker levels were collected.All patients underwent HR-pQCT and were compared with 1:2 age-and gender-matched healthy controls.The relationships between bone metabolic markers,HR-pQCT parameters and clinical biochemical indexes were analyzed.Gene testing was performed on 22 patients to identify the types of gene mutations.After stratification by mutation types,comparisons were conducted between truncated mutation group and non-truncated mutation group.Results1.The volumetric bone mineral density,bone geometry and bone microstructural parameters of patients with Gitelman syndrome were superior to those of the same age and gender,mainly characterized by the reduction of bone cross-sectional area,the increase of volumetric bone density and the improvement of bone microstructure.At the distal radius,the male GS patients had lower total area(297.07±48.67 vs 357.83±60.48,P=0.002),lower cortical area(224.94± 45.00 vs 282.44±57.04,P=0.002),higher total volume bone mineral density(vBMD)(374.36±64.55 vs 329.06±54.11,P=0.021)and higher cortical vBMD(927.92±54.34 vs 888.66±37.89,P=0.009).The female patients had higher cortical vBMD(975.32±37.63 vs 942.18±35.70,P=0.011),as well.Both male and female patients presented higher trabecular number(Malel.686±0.243 vs 1.426±0.202,P=0.001;Female 1.565±0.267 vs 1.296±0.266,P=0.005),lower trabecular separation(Male 0.559±0.102 vs 0.669±0.113,P=0.004;Female 0.594(0.552,0.646)vs 0.693(0.614,0.877),P=0.011)and lower inhomogeneity of network(Male 0.211±0.045 vs 0.267±0.049,P=0.001;Female 0.208(0.187,0.230)vs 0.264(0.228,0:336),P=0.008).At the distal tibia,female GS patients showed higher total vBMD(312.29±54.54 vs 277.15±38.15,P=0.025)and higher cortical vBMD(981.71±39.91 vs 927.94±55.26,P=0.004).Male GS patients had higher trabecular number(1.564(1.333,1.786)vs 1.233(1·118,1.354),P<0.001)and lower trabecular separation(0.618±0.094 vs 0.785 ±0.124,P<0.001).Both genders demonstrated lower cortical porosity(Male 0.821±0.372 vs 2.429±0.972,P0.001;Female 0.400(0.300,0.550)vs 1.400(0.800,2.550),P0.001)and inhomogeneity of network(Male 0.245 ± 0.040 vs 0.328 ± 0.057,P<0.001;Female 0.272 ± 0.063 vs 0.330±0.088,P=0.039).2.The relationship between bone metabolic markers,HR-pQCT parameters and clinical biochemical indexes was not specified.GS patients with a minimum serum potassium level no more than 2.0mmol/L may have better bone quality.3.31 mutations of SLC12A3 gene were identified in 22 patients,6 of which were novel.After stratification by mutation types,no siginicant difference in bone metabolic markers and HR-pQCT parameters were found between truncated mutation group and non-truncated mutation group.Conclusions1.Patients with Gitelman syndrome were demonstrated to be better than healthy people of the same gender and age in terms of volume bone density,bone geometry and bone microstructure assessed by HR-pQCT.2.No specific relationship between clinical biochemical indicators,genotypes and bone phenotypes of GS was found.GS patients with a minimum serum potassium level no more than 2.0mmol/L may have better bone quality.3.No specific relationship between clinical biochemical indicators,mutation types and bone phenotypes of GS was found. |
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