Objective:To investigate potential factors associated with nephrocalcinosis in children with X-linked hypophosphatemic rickets (XLH).Methods:A case-control study was conducted involving XLH children who were regularly followed up at Children′s Hospital of Nanjing Medical University, from January 2016 to January 2024.Patients diagnosed with nephrocalcinosis were assigned to the case group, and those without nephrocalcinosis served as controls.A retrospective analysis was performed to examine the correlation between nephrocalcinosis and laboratory parameters, as well as the diagnostic value of relevant factors.Multivariable Logistic regression was used to identify factors associated with nephrocalcinosis in children with XLH.Receiver operating characteristic (ROC) curves were plotted for the significant factors, and the areas under the curve (AUC) were compared using Delong′s test to evaluate differences in predictive performance.Results:Univariate analysis revealed significant differences between the case and control groups in serum calcium, urinary calcium, urinary calcium/creatinine ratio, urinary phosphorus, and renal tubular maximum reabsorption rate of phosphate/glomerular filtration rate (TmPi/GFR) (all P<0.05).However, multivariate logistic regression analysis identified only urinary calcium ( B=0.489, P=0.001) and TmPi/GFR ( B=-0.886, P=0.007) as independent predictors, while the urinary calcium/creatinine ratio was not statistically significant.The sensitivity, specificity, optimal cutoff value, and AUC for urinary calcium in predicting nephrocalcinosis were 0.842, 0.833, 0.614 mmol/L, and 0.851 ( P<0.01), respectively.For TmPi/GFR, the corresponding values were 0.900, 0.877, 0.573 mmol/L, and 0.875 ( P<0.01).The Delong test showed no significant difference in AUC between the combined indicator and TmPi/GFR ( Z=-1.555, P=0.120) or urinary calcium alone ( Z=-1.598, P=0.110). Conclusions:Urinary calcium and TmPi/GFR are significantly associated with nephrocalcinosis in children with XLH and demonstrate good predictive performance for early detection.The combination of these two indicators does not outperform either individual marker in diagnostic accuracy.

Objective:To investigate potential factors associated with nephrocalcinosis in children with X-linked hypophosphatemic rickets (XLH).Methods:A case-control study was conducted involving XLH children who were regularly followed up at Children′s Hospital of Nanjing Medical University, from January 2016 to January 2024.Patients diagnosed with nephrocalcinosis were assigned to the case group, and those without nephrocalcinosis served as controls.A retrospective analysis was performed to examine the correlation between nephrocalcinosis and laboratory parameters, as well as the diagnostic value of relevant factors.Multivariable Logistic regression was used to identify factors associated with nephrocalcinosis in children with XLH.Receiver operating characteristic (ROC) curves were plotted for the significant factors, and the areas under the curve (AUC) were compared using Delong′s test to evaluate differences in predictive performance.Results:Univariate analysis revealed significant differences between the case and control groups in serum calcium, urinary calcium, urinary calcium/creatinine ratio, urinary phosphorus, and renal tubular maximum reabsorption rate of phosphate/glomerular filtration rate (TmPi/GFR) (all P<0.05).However, multivariate logistic regression analysis identified only urinary calcium ( B=0.489, P=0.001) and TmPi/GFR ( B=-0.886, P=0.007) as independent predictors, while the urinary calcium/creatinine ratio was not statistically significant.The sensitivity, specificity, optimal cutoff value, and AUC for urinary calcium in predicting nephrocalcinosis were 0.842, 0.833, 0.614 mmol/L, and 0.851 ( P<0.01), respectively.For TmPi/GFR, the corresponding values were 0.900, 0.877, 0.573 mmol/L, and 0.875 ( P<0.01).The Delong test showed no significant difference in AUC between the combined indicator and TmPi/GFR ( Z=-1.555, P=0.120) or urinary calcium alone ( Z=-1.598, P=0.110). Conclusions:Urinary calcium and TmPi/GFR are significantly associated with nephrocalcinosis in children with XLH and demonstrate good predictive performance for early detection.The combination of these two indicators does not outperform either individual marker in diagnostic accuracy.

This study aimed at conducting retrospective analysis of the clinical symptoms and genetic mutations in 20 children with Gitelman syndrome treated at the Affiliated Children′s Hospital of Nanjing Medical University from August 2015 to November 2022 and also explored the molecular mechanism of the pathogenic high-frequency mutation D486N in the Chinese population.