ABCB11 and cholelithiasis: Alternatively, defects in other regions of the gene or in other genes may also be involved, and some evidence from animal studies has pointed to Abcb 11 (previously called the bile salt export pump, BSEP), Abcc 2 (previously referred to as multidrug resistance related protein 2, or MRP2) or Abcg5/Abcg8 as other possible candidate genes underlying susceptibility to cholelithiasis [15-19] or phospholipid secretion disruption [20].