It was thought that they could have redundant functions, but their distinct expression patterns in different tissues and cell lines have suggested that they are not redundant; RhoGDI1 knockout mice, described by Towaga et al., is characterized by the development of kidney failure and infertility [34], whereas RhoGDI2 knockout mice showed a mild alteration in the oxidative state in phagocytic cells [35]. The gene discussed is ARHGDIB; the disease is Infertility.