Abstract

HNF1B (Hepatocyte nuclear factor 1 beta) deficiency syndrome is a rare genetic disease caused by a pathogenic variant or deletion of the HNF1B gene. HNF1B encodes a protein that plays a role in the normal development and functioning of liver, kidneys, pancreas, brain, and the urogenital system. At first disease was named renal cysts and diabetes syndrome (RCAD), but in recent years other organs have been shown to be affected by the pathogenic variant of the gene, which has led to a definition of multisystem disease with variable clinical phenotype: syndrome is characterized by presence of MODY5, dorsal agenesis of the pancreas, cholangiociliopathy, urogenital system and neuropsychiatric disorders with varying degree of organ involvement. Syndrome should be suspected in case of patient with renal cysts or renal failure as well as MODY, hypothesis is supported by patients having liver, urogenital or cognitive changes. Syndrome awareness is low and multifacetedness of the disorder requires a multidisciplinary approach, which makes diagnosis difficult and might lead to patients being undiagnosed. In this article we present a case report of a 33-year-old male patient as well as review of the existing literature. Patient was diagnosed with HNF1B deficiency syndrome (in the context of 17q12 microdeletion), with MODY, pancreatic dorsal agenesis (chronic pancreatitis and pancreatic exocrine insufficiency), mild cholestatic liver disease (with mild ductopenia and stage 1 fibrosis on liver biopsy) and renal cysts (no renal failure at the time of the diagnosis). The prevalence and natural history of the disease remains largely elusive and new data is essential, as it might help establish recommendations about treatment and surveillance of these patients in the future.