HNF1B encodes a transcription factor essential for multi-organ development, particularly during embryogenesis. The protein functions by binding to specific DNA sequences and regulating gene expression in renal, pancreatic, hepatic, and genitourinary tissues 1. HNF1B controls critical developmental processes including nephrogenesis, cellular polarity, tight junction formation, and ion transport in renal tubules 1. Single-cell analysis has confirmed HNF1B's role in kidney development, with enhancer elements driving its transcription during organoid differentiation 2. Heterozygous mutations in HNF1B represent the most common known monogenic cause of developmental kidney disease, operating through a haploinsufficiency mechanism 3. The clinical spectrum is remarkably broad, including renal cysts, diabetes mellitus, pancreatic hypoplasia, genital tract malformations, and liver abnormalities 34. HNF1B mutations account for approximately 19% of monogenic diabetes cases in patients clinically suspected of having maturity-onset diabetes of the young (MODY) 5. The gene is also associated with Mayer-Rokitansky-Küster-Hauser syndrome through 17q12 deletions 6. A clinical scoring system has been developed to guide genetic testing decisions 7.