We appreciate the insightful comments of Drs Finsterer and Frank1 on our recent case report.2 The diagnosis of ADPKD was based on the Japanese PKD clinical guidelines,3 which have 2 different criteria according to whether family history is present, and includes computed tomography, magnetic resonance imaging (MRI), and ultrasonography findings for diagnosis. For patients 16 years and older without a family history, in whom other cystic kidney diseases are excluded, more than 5 cysts detected in each kidney by computed tomography, MRI, or ultrasonography is diagnostic of ADPKD.