RESUMO
BACKGROUND: Gitelman syndrome (GS) is a rare inherited autosomal recessive tubulopathy, characterized clinically by hypokalemia, hypomagnesemia, hypocalciuria, and metabolic alkalosis, and is caused by an inactivating mutation in SLC12A3. GS is prone to misdiagnosis when occurring simultaneously with hyperthyroidism. It is important to consider the possibility of other diseases when hyperthyroidism is combined with hypokalemia, which is difficult to correct. CASE SUMMARY: A female patient with hyperthyroidism complicated with limb weakness was diagnosed with thyrotoxic hypokalemic periodic paralysis for 4 mo. However, the patient's serum potassium level remained low despite sufficient potassium replacement and remission of hyperthyroidism. GS was confirmed by whole exome and Sanger sequencing. Gene sequencing revealed compound heterozygous mutations of c.488C>T (p.Thr163Met), c.2612G>A (p.Arg871His), and c.1171_1178dupGCCACCAT (p.Ile393fs) in SLC12A3. Protein molecular modeling was performed to predict the effects of the identified missense mutations. All three mutations cause changes in protein structure and may result in abnormal protein function. All previously reported cases of GS coexisting with autoimmune thyroid disease are reviewed. CONCLUSION: We have identified a novel compound heterozygous mutation in SLC12A3. The present study provides new genetic evidence for GS.
RESUMO
OBJECTIVE: This study aims to explore the factors influencing the renal glucose threshold (RTG) in patients with newly diagnosed type 2 diabetes mellitus (T2DM). METHODS: A cross-sectional study was conducted on 1009 hospitalized patients with T2DM using stratified random sampling. Blood glucose was monitored using a dynamic blood glucose monitor to obtain the mean blood glucose (MBG), which is used to calculate the RTG. The factors influencing the RTG were then analyzed. RESULTS: The mean RTG in patients with newly diagnosed T2DM was 203.58 ± 55.22 mg/dl. The correlation between the RTG and the various variables was analyzed, and the results demonstrated that the RTG was correlated with the patient's age (r = -0.14539, P = 0.0001); MBG (r = -0.35009, P = 0.0001); renal long neck (r = 0.16762, P = 0.0001); homeostatic model assessment for insulin resistance (r = -0.38322, P = 0.0001); homeostatic model assessment for beta-cell function (r = -0.22770, P = 0.0001); and the levels of glycated hemoglobin (HbA1c; r = 0.98994, P = 0.0001), blood urea nitrogen (r = -0.11093, P = 0.0004), creatinine (r = -0.26414, P = 0.0001), uric acid (r = -0.20149, P = 0.0001), total cholesterol (r = 0.13192, P = 0.0001), low-density lipoprotein (r = 0.12466, P = 0.0001), thyroid-stimulating hormone (r = -0.06346, P = 0.0460), beta-2 microglobulin (r = -0.08884, P = 0.0056), and 24-hour urine glucose (r = 0.32115, P = 0.0001). Multiple linear stepwise regression analysis revealed that the HbA1c, 24-hour urine glucose, estimated glomerular filtration rate (eGFR), D-dimer, and body mass index (BMI) should be included in the final model, and HbA1c had the greatest impact on the RTG followed in descending order by the 24-hour urine glucose, eGFR, D-dimer, and BMI (P < 0.05). CONCLUSION: The RTG increases in most patients with newly diagnosed diabetes. The risk factors for the RTG are HbA1c, 24-hour urine glucose, eGFR, D-dimer, and BMI.