PKHD1 and Complex Cyst of Kidney: Gulati and colleagues observed that collagen IV gene mutations were present in a series of patients with bilateral kidney cysts, suggesting that type IV collagen mutations may be present in ADPKD patients without mutations in the PKD1 or PKD2 genes [16].With regard to PKHD1, although the perinatal manifestation is the most common form, later onset was also described in the literature [23].