HNF1B and renal cysts and diabetes syndrome: It is caused by a heterozygous pathogenic variant in HNF1A, which encodes a transcription factor (hepatocyte nuclear factor 1A) that is critical for pancreatic differentiation and function (6), whereas the MODY5 subtype present in the patient described herein is caused by a 17q12 deletion included in the HNF1B gene.