Prenatal Therapies Mucopolysaccharidosis type VII (MPS7) is a rare and severe lysosomal storage disorder that causes dysfunction of multiple organs, including the brain. By the time of birth, the organ damage may already be severe and the fetus may not survive. Thus, the prenatal period provides the most promising opportunity for intervention. Nguyen et al. assessed two prenatal approaches—in utero enzyme replacement therapy and in utero hematopoietic stem cell transplantation—and demonstrated the potential of these treatments to improve survival and functional outcomes in a mouse model of MPS7. Sci. Transl. Med. 12 , eaay8980 (2020).