While patient III-1 presented with morphologically normal kidneys and unimpaired organ function (serum creatinine 1.1 mg/dl, eGFR 92 ml/min/1.73 m2, no proteinuria), his son (IV-1) developed chronic kidney failure (serum creatinine 3.98 mg/dl, cystatin C 5.38 mg/l, eGFR 11 ml/min/1.73 m2, protein to creatinine ratio 2.9 g/g, albumin to creatinine ratio 2.3 g/g) at age two years due to bilateral kidney dysplasia and underwent preemptive living kidney transplantation with the organ donated from his mother. The gene discussed is CST3; the disease is chronic renal failure syndrome.