PKD1 lays immediately adjacent to TSC2 and deletions involving both genes, the PKD1/TSC2 contiguous gene syndrome (CGS), are characterized by severe ADPKD, plus TSC. mTOR inhibitors have proven effective in reducing angiomyolipoma (AML) in TSC and total kidney volume in ADPKD but without a positive effect on renal function.
This should not be dismissed as renal cystic disease of TSC or as ADPKD because the diagnosis of TSC2/ADPKD1 contiguous gene syndrome has implications for patient management and prognosis.
Although extremely rare, TSC and autosomal dominant polycystic kidney disease (ADPKD) can co-exist in the same patient as a result of concurrent deletion of both polycystic kidney disease (PKD) 1 and TSC2 genes present on the chromosome 16p13.3.
The association of tuberous sclerosis complex (TSC) and autosomal dominant polycystic kidney disease (ADPKD), termed TSC2/PKD1 contiguous gene syndrome, is a result of molecular defect demonstrating by deletion disrupting TSC2 and PKD1.
Tuberous sclerosis complex (TSC) was instrumented for identification of the gene causing autosomal dominant polycystic kidney disease type 1 (PKD1) because a patient showing both diseases gave rise to the suggestion that the TSC2 gene is located in close vicinity on chromosome 16p13.
Variance component analysis in ADPKD populations indicates that genetic modifiers are important, but few such factors (beyond co-inheritance of a TSC2 mutation) have been identified.
Among the inherited polycystic kidney diseases we include autosomal recessive polycystic kidney disease (ARPKD) and autosomal dominant polycystic diseases such as von Hippel-Lindau disease, tuberous sclerosis complex (TSC1 and TSC2), and autosomal dominant polycystic kidney disease (ADPKD).
A TSC2-PKD1 contiguous gene syndrome caused by chromosomal microdeletions disrupting both the TSC2 and PKD1 genes has been identified in patients with TSC and early-onset severe ADPKD.
The characteristics of the contiguous PKD1/TSC2 syndrome phenotypes and the data from Krd mice imply that TSC2 and PAX2 may also serve as potential modifiers for the disease severity of autosomal-dominant polycystic kidney disease.
Major genes which cause tuberous sclerosis (TSC) and autosomal dominant polycystic kidney disease (ADPKD), known as TSC2 and PKD1 respectively, lie immediately adjacent to each other on chromosome 16p.