Progressive Polycystic Kidney Disease in an Infant Girl With TSC2/PKD1 Contiguous Gene Syndrome

TSC2/PKD1 contiguous gene syndrome is caused by deletions involving the TSC2 and PKD1 genes that lead to tuberous sclerosis complex and autosomal dominant polycystic kidney disease. It is characterized by early-onset severe cystic kidney disease with progressive enlargement of the kidneys and the cysts. As it can lead to early hypertension and an accelerated decline of kidney function, early genetic testing is needed for early diagnosis of this syndrome, and more frequent imaging-based examinations are necessary to assess disease progression and determine appropriate management. We report the case of an infant girl with TSC2/PKD1 contiguous gene syndrome who presented with epileptic seizures. Brain magnetic resonance imaging (MRI) revealed subependymal nodules and cortical tubers, and abdominal MRI revealed polycystic kidney lesions and enlargement of both kidneys. TSC2/PKD1 contiguous gene syndrome was suspected from her radiological features, and we confirmed the presence of a deletion in the girl's genome, which included the TSC2 and PKD1 genes, via microarray analysis. Thereafter, we evaluated the change in kidney size via repeated abdominal MRI. The polycystic kidney lesions enlarged, and the patient developed hypertension in early childhood, for which we administered an angiotensin-converting enzyme inhibitor. We emphasize the importance of evaluation with longitudinal abdominal imaging because renal cysts tend to enlarge rapidly and induce hypertension, as demonstrated in our case.