The influence of polymorphisms in CYP3A4 on clinical outcomes was evaluated in four studies: AKI in four studies (Hamadeh et al., 2019; Ho et al., 2024; Khaled et al., 2016; Zhu et al., 2020), GVHD in three studies (Ho et al., 2024; Khaled et al., 2016; Suetsugu et al., 2019), TMA in one study (Khaled et al., 2016) and OS, RFS and NRM in one study (Ho et al., 2024). Here, CYP3A4 is linked to graft versus host disease.