Different functions of IdoA have been found both in vitro and in vivo. The human situations where DS-epi1 expression is changed in tumours and where D4ST1 mutations lead to deranged connective tissue have been highlighted. The importance of IdoA is evident from observations of DS-epi1 KO mice, which die perinatally and/or present gastroschisis. Furthermore, a decrease of IdoA leads to an altered collagen structure, resulting in a decreased tensile strength. Provocation of mice with targeted DS-epi1 and 2 will most likely provide more information about other biological functions of IdoA. Other data indicate the importance of IdoA in cytokine activity and storage, cell proliferation and migration, the control of coagulation, the formation of autoantibodies, the control of stem cell stability and differentiation.
