COL5A1 and hemochromatosis: And finally, other SNPs such as the beta-3 adrenergic receptor ADRB3 rs4994 (Santiago et al., 2011), the GA-binding protein transcription factor, subunit beta 1 GABPB1 rs12594956 (Eynon et al., 2010a, 2013), the collagen type V alpha 1 chain COL5A1 rs12722 (Brown et al., 2011; Posthumus et al., 2011) and the hemochromatosis HFE rs1799945 (Grealy et al., 2015) have also been associated with better endurance performance, although the scientific evidence support for these associations is still scarce.