Abstract: A 12yearold male with 4year course presented with low molecular weight proteinuria,no microscopic hematuria,normal blood pressure and renal function,proximal renal tubule injury (hypouricemia glucoseuria,positive urine glucose),hypercalciuria.Renal ultrasound revealed bilateral kidney crystal.Renal biopsy showed tubulointerstitial lesions.Nextgeneration sequencing（NGS）revealed an insertion mutation (c.2146_2147insAC) in the CLCN5 gene,which resulted in a frame shift mutation.The child had a semizygotic mutation.The final diagnosis was Dent disease type 1.

Key words: Dent disease type 1, hereditary tubular disease, CLCN5 gene, X-linked recessive inheritance