Purpose or Case Report: HNF1B nephropathy is a hereditary renal disease caused by mutations in the HNF1B gene, transmitted in an autosomal dominant manner but frequently occurring as de novo mutations. This genetic variability complicates diagnosis, as family history of renal disease may be absent. Clinical presentation is heterogeneous, with onset in both children and adults, and may include renal dysfunction, metabolic abnormalities, and in some cases early-onset diabetes.

In the pediatric setting, imaging plays a crucial role in raising suspicion of HNF1B nephropathy. Prenatal ultrasound and MRI may reveal echogenic kidneys or renal hypoplasia in the third trimester, while postnatal ultrasound may show variable findings such as increased renal echogenicity, renal cysts, and reduced renal size. These abnormalities can mimic more common entities, highlighting the importance of a systematic imaging approach.

This educational exhibit reviews the prenatal and postnatal imaging findings of HNF1B nephropathy in children emphasizing key imaging clues that should raise diagnostic suspicion when encountering cystic or dysplastic renal patterns. The exhibit also includes discussion of the differential diagnosis with other conditions associated with renal cysts, such as autosomal dominant polycystic kidney disease (ADPKD), autosomal recessive polycystic kidney disease (ARPKD), multicystic renal dysplasia, Meckel–Gruber syndrome and other ciliopathies. Recognizing the imaging spectrum of HNF1B nephropathy is essential to avoid misclassification as nonspecific chronic interstitial nephropathy and to ensure timely genetic testing, counseling, and long-term multidisciplinary management.
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