Two brothers with identical variants of the CLCN5 gene-one developing Dent's disease

Dent's disease is characterized by manifestations of proximal tubule dysfunction including hypercalciuria, kidney stones, proteinuria, rickets and progressively declining kidney function. The diagnosis is based on the presence of low-molecular-weight proteinuria, hypercalciuria and at least one of the following: nephrocalcinosis, kidney stones, haematuria, hypophosphataemia or renal insufficiency. Dent's disease is a hereditary condition that is caused by variants in the CLCN5 gene or the OCRL1 gene and affects only males. Herein, we report on two brothers who were found to have a previously reported disease-causing variant in the CLCN5 gene. One sibling had nephrocalcinosis, proteinuria and hypercalciuria, whereas the other sibling was asymptomatic and had normal laboratory findings.