A different SCD model, commonly referred to as the Townes mouse, was generated by using homologous recombination to replace adult-expressed mouse α-globin genes with human HBA1, and adult-expressed mouse β-like globin genes with tandemly linked genomic segments of human HBG1 and HBBS (Wu et al., 2006). Here, HBG1 is linked to Schnyder corneal dystrophy.