HMOX1 and Fabry disease: Endogenous antioxidant defense in terms of HO-1, which we have previously shown to be reduced in treated FD patients compared to healthy subjects (13) was, in this study, increased by ERT treatment compared to baseline and further increased by adjuvant GT treatment, providing more evidence on the role of OS and OS reduction in addition to early initiation of ERT and antioxidant therapies in FD patients.