[Clinical features and genetic variants of Dent disease in 10 children]

Objective: To summarize the clinical features and genetic analysis results of 10 children with Dent disease. Methods: The clinical data and gene test results of 10 boys aged from 8 months to 12 years with Dent disease diagnosed in Children's Hospital of Nanjing Medical University from January 2014 to July 2017 were analyzed retrospectively. Results: All patients had insidious onset, 5 cases were found to have proteinuria on routine urine examination after hospitalization duo to other diseases, 4 cases were admitted to hospital because increased foams in the urine, and 1 case was found to have proteinuria on health checkup. All cases presented with low molecular weight proteinuria, urine protein electrophoresis showed that the proportion of low molecular weight protein was greater than 50%, 7 cases had nephrotic-range proteinuria, but none had hypoproteinemia. Six cases had hypercalciuria, 3 cases had nephrocalcinosis, 1 case had nephrolithiasis, 2 cases had glomerular microscopic hematuria, in 1 case urine glucose wa weakly positive but blood glucose was normal. All patients had normal renal function, normal serum calcium, no hypophosphoremia and none had rickets. Genetic analysis results showed that 7 patients with variants in the CLCN5 gene, including 2 nonsense variants (p.R637X, p.Y143X), 3 missense variants (p.A540D, p.G135E, p.G703V), 1 deletion variant (exons 9, 10, 11, 12, 13, 1 missing), and 1 frameshift variant (p.T260Tfs*10). Three cases had missense variants of OCRL gene (p.I274T, p.I371T, p.F399S). Except for p.R637X and p.I274T, the other 8 cases had newly discovered variants. Five patients underwent a renal biopsy, the biopsy revealed focal global glomerulosclerosis in 3 patients, mild mesangial proliferative glomerulonephritis in 1 patient and renal minimal change in 1 patient. Mild focal tubular atrophy and interstitial fibrosis were noted in three cases. Mild segmental foot process effacement was noted under electron microscope in all five cases. Conclusions: All the children with Dent disease had insidious onset, low molecular weight proteinuria is the main clinical manifestation, most cases presented with nephrotic-range proteinuria, but there was no hypoalbuminemia, some cases were not associated with hypercalciuria. The pathogenic genes in most cases were CLCN5 and a few were OCRL. The types of genetic variation include missense variant, nonsense variant, deletion variant and frameshift variant. Although Dent disease is a renal tubular disease, renal biopsy suggests that most cases are associated with glomerular lesions.