PKD2 and spontaneous coronary artery dissection: Another factor rarely associated with SCAD is autosomal dominant polycystic kidney disease (ADPKD) [4], a prevalent hereditary renal cystic disease, which is characterized by genetic abnormalities on the polycystic-kidney-disease 1 (PKD1) locus or chromosome 4 (the polycystic-kidney-disease 2 (PKD2) locus).