Background: The proband, a 33-year-old woman, presented with renal cysts, mild renal failure and a renal tumor. One of the proband's two sons had hyperechogenic kidneys and the other had renal cortical microcysts. Her 71-year-old mother had mild renal failure and small renal cysts.
Investigations: Ultrasonography, blood and urine analysis, MRI, CT scan, and genetic investigations focusing on the transcription factor 2 (TCF2) gene which encodes hepatocyte nuclear factor 1 beta.
Diagnosis: The proband was diagnosed with cystic kidney disease and chromophobe renal cell carcinoma, characterized by a 46delC germline mutation of TCF2 and a complete somatic deletion of TCF2 in the renal tumor. The germline TCF2 mutation was also present in the proband's sons and mother. Pancreas atrophy was detected in the proband and her mother.
Management: Tumorectomy followed by radical nephrectomy of the left kidney 4 years later. Lisinopril (5 mg/day) and lifelong follow-up. The patient's sons will be regularly screened for progressive renal disease, diabetes mellitus and chromophobe renal cell carcinoma.