Protein S deficiency in a living liver donor

Protein S deficiency is a thrombophilia associated with increased risk of thromboembolic episodes in affected patients. Traditionally, protein S deficiency in a potential donor was considered an absolute contraindication to living donor liver transplantation, both due to the increased risk incurred by the thrombophilic donor as well as the risk of transmitting the thrombophilia to the liver recipient, as protein S is predominantly produced by the liver. We present the first successful case of living donor liver transplantation using a donor with asymptomatic protein S deficiency. Interestingly, whereas the donor continued to have protein S levels approximately 50% of normal, the recipient maintained normal levels of protein S post-transplant, potentially due to compensation by extra-hepatic protein S production. We discuss the prior literature of protein S deficiency acquired via liver transplantation, and we evaluate potential criteria by which the safety of transplants utilizing this pool of donors may be enhanced.