CYP2B6 is an important enzyme in the bioactivation of cyclophosphamide and the *6 haplotype corresponding to rs3745274(G > T) and rs2279343(A > G), was associated with SOS in a study by Rocha et al. (OR 3.5, CI 1.1–10.9) [40]. The gene discussed is CYP2B6; the disease is spondylo-ocular syndrome.