A Case of TSC2/PKD1 Contiguous Gene Deletion Syndrome With Proven Kidney Pathology

TSC2/PKD1 contiguous gene deletion syndrome (PKDTS) is characterized by poor renal prognosis. We encountered a female patient with a history of facial angiofibromas since childhood who developed seizures and was subsequently diagnosed with tuberous sclerosis complex. The patient later progressed to kidney failure requiring replacement therapy at 23 years of age. Imaging studies showed polycystic kidney disease (PKD) and angiomyolipoma (AML), followed by renal hemorrhage in both kidneys. Genetic testing showed a heterozygous deletion involving the TSC2 and PKD1 genes on chromosome 16, confirming the diagnosis of PKDTS. To elucidate the cause of her kidney dysfunction, a pathohistological analysis of renal tissue showed that most of the renal parenchyma was replaced by cystic formations and scattered AML masses. The cysts were derived from both the proximal and distal tubules, a feature consistent with PKD. Renal hemorrhage was presumed to result from vascular disruption and rupture of the internal elastic lamina because of cyst and AML progression. The combination of extensive renal cyst formation related to PKD1 deletion and AML lesions corresponding to TSC2 deletion may contribute to the rapid progression of kidney dysfunction in patients with PKDTS.