Large Kidney Cysts in HNF1B Nephropathy Mimicking Autosomal Dominant Polycystic Kidney Disease.

Abstract

Hepatocyte nuclear factor 1 beta (HNF1B) nephropathy is a rare autosomal dominant monogenic kidney disease. We present a case mimicking autosomal dominant polycystic kidney disease (ADPKD), highlighting the phenotypic heterogeneity of HNF1B-related disease. A 37-year-old man presented with hypertensive urgency, accompanied by flank pain and abdominal distension. Despite the absence of familial kidney disease, imaging revealed large bilateral kidney cysts resembling ADPKD. We initially suspected de novo ADPKD. However, negative genetic testing results for PKD1 and PKD2 led to a 43-gene cystic kidney sequencing panel which identified a deletion encompassing the entire HNF1B gene. To alleviate discomfort caused by the kidney cysts, ultrasound-guided aspiration and foam sclerotherapy were performed. Tolvaptan, used for treating high-risk ADPKD, was not prescribed after confirming the diagnosis was HNF1B nephropathy. A diagnosis of HNF1B nephropathy was reached following gene panel testing. Abdominal symptoms improved following cyst aspiration and foam sclerotherapy. HNF1B nephropathy has a variable presentation but can lead to cysts appearing like ADPKD. A 43-gene cystic kidney sequencing panel identified the diagnosis in this uncertain case.