TDO2 and Huntington disease: KMO is an important therapeutic target for multiple organ dysfunction, particularly that triggered by acute pancreatitis and the systemic inflammatory response,1, 2 and for Huntington's disease.3 KMO also has a significant role in the immune adaptive response.4 TRP is converted to KYN by tryptophan-2,3-dioxygenase (TDO) and indoleamine-2,3-dioxygenases (IDOs), following which KYN has several potential fates.