Other pathogenic features have been identified in ARPKD, as well as alterations in extracellular matrix (ECM) and metalloproteinase expression (MMPs) [152,153], upregulation of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1 alpha (HIF-1α) in Pkhd1 deficient cells [139], upregulation of peroxisome-proliferator-activated receptor-γ (PPAR-γ) in animal models [154,155], or metabolic alterations [156]. The gene discussed is PKHD1; the disease is autosomal recessive polycystic kidney disease.