Autosomal Dominant Polycystic Kidney Disease (ADPKD) and Autosomal Recessive Polycystic Kidney Disease (ARPKD) are types of PKD, but their difference is the way they are genetically transmitted.
ADPKD is inherited by the patient from one or both parents who are a dominant carrier, whereas ARPKD is inherited from one or both parents who are a recessive carrier.