To explore the clinical characteristics of children with Dent -1 disease and review the related literatures to improve the clinicians′ recognition of this disease.

One boy with Dent-1 disease who was diagnosed by clinical manifestations and gene test at the Guangzhou Women and Children′s Medical Center on November 26, 2015 was selected as the research subject. The clinical data of the patient was collected so as to summarize its clinical characteristics and the process of diagnosis and treatment by retrospectively analysis method. The western literatures related with Dent-1 disease were reviewed from PubMed database and Foreign Medicine Information Resource Retrieval Platform of Shenzhen Maitre Technology Co. Ltd. by the search strategy with " Dent disease" as the subject heading and " Dent′s disease" as the key word. Chinese literatures related with Dent-1 disease were reviewed from Wanfang Data Knowledge Service Platform and China National Knowledge Infrastructure by the search strategy with " Dent disease" as the key word. All literatures were reviewed from October 1997 to December 2017. This study met the requirements of the World Medical Association Declaration of Helsinki revised in 2013.

The results of the study on the male patients with Dent-1 disease showed as follows. ①Proteinuria was found by urine routine during physical examination. ②The proteinuria was as high as the diagnostic criteria for nephrotic syndrome without obvious edema, high serum cholesterol and hypoproteinemia. The urinary renal tubular test showed that the level of urine low-molecular-weight protein (LMWP) including urine α1-microglobulin (MG), urine β2-MG, and urine retinol-binding protein (URBP) were obviously increased (more than five times higher than the upper limit of normal reference level) and the urinary protein electrophoresis pointed to LMWP. According to the results of renal biopsy, the patient was misdiagnosed as mild mesangial proliferative glomerulonephritis, and received ineffective treatment of hormones and immunosuppressants. The patient had hypercalciuria, and his urinary system ultrasound and renal functions were normal. ③Genetic test results showed that a c. 2119C>T hemizygote mutation in CLCN5 gene was found in the patient, but this mutation was not found in his mother or sister. He was treated with low oxalate, low sodium, low calcium diet, and drinking lots of water. Besides, the ratio of urinary calcium and urinary creatinine decreased to normal by the treatment of hydrochlorothiazide 1-2 mg/(kg·d) for three months, however it increased after drug withdrawal for one month. The amount of urine protein quantification did not decrease obviously after fosinopril 0.2-0.3 mg/(kg·d) treatment for nine months.

For patients with LWMP urine as the main clinical manifestation and proteinuria which is as high as the diagnostic criteria for nephrotic syndrome, genetic testing should be conducted to confirm whether it is Dent-1 disease or not, avoiding unnecessary invasive and hemorrhagic renal biopsy and a trial of steroid and immunosuppressive treatment. Hypercalcinuria can be controlled by hydrochlorothiazide treatment, and it is necessary to develop a standardized clinical guideline for Dent-1 disease treatment.