We report two cases of HNF1-β gene variation diagnosed in infancy, in whom fetal ultrasonography revealed enhanced echogenicity and multiple cysts in the renal parenchyma of both patients. They were initially diagnosed as autosomal recessive polycystic kidney disease. Gene testing showed a variation of HNF1-β gene, one showed chromosome 17q12 deletion including HNF1-β, the other was a de novo nonsense mutation in the HNF1-β gene. The two children showed different renal function states. Extrarenal phenotypes also vary widely according to HNF1-β gene variation including early-onset diabetes, autism spectrum, cognitive disorders, liver function abnormalities, and genital malformations, etc. We emphasize the importance of performing gene detection in order to make an accurate diagnosis, especially in those with fetal hyperechogenic kidneys, and so as to carry out reasonable multidisciplinary management. Early intervention for diabetes and neurodevelopmental disorders are especially important.