When tested in a Mucopolysaccharidosis type II (MPS II) murine model during HSPC-LVGT using pCCL.MND lentiviral vectors (Catalano et al, 2023, 2024), tagging of IDS (Iduronate 2-sulfatase, defective in MPS II) with SWAP variants resulted in a therapeutic outcome that matched unmodified IDS.IGF2, trended superior compared to central loop-deleted IGF2 (IGF2del), and outperformed untagged IDS. This evidence concerns the gene IGF2 and mucopolysaccharidosis type 2.