Other gene variants have already been found as predisposing factors for AT, among these are variants within Collagen, type V, alpha 1 (COL5A1; Mokone et al., 2006), matrix metallopeptidase 3 (MMP3; Raleigh et al., 2009), TIMP Metallopeptidase Inhibitor 2 (TIMP2; El Khoury et al., 2013), Tenascin C (TNC; Collins and Raleigh, 2009), growth differentiation factor 5 (GDF5; Posthumus et al., 2010) genes. The gene discussed is COL5A1; the disease is ataxia telangiectasia.