TGFB1 and Ehlers-Danlos syndrome: Importantly, mouse Slc39a13 carrying the homologous G to A substitution (G74D, Figures 7C and 7D) as well as human SLC39A13 having the G to A mutation obtained from EDS patients (data not shown) was unable to fully rescue the unresponsiveness of osteoblasts and fibroblasts isolated from Slc39a13-KO mice against BMP and TGF-β, respectively, indicating that this mutation causes a loss of function.