The α-subunit (HIF-α) undergoes proteolysis during normoxia by the Von Hippel-Lindau (VHL) tumour suppressor [18] and patients with Von Hippel-Lindau disease (an autosomal dominant syndrome that occurs secondary to germline mutations in the VHL tumour suppressor gene) develop multiple simple renal cysts at a young age and renal cell carcinoma later in life [18, 22]. This evidence concerns the gene VHL and cystic kidney disease.