[Fetal therapy of skeletal dysplasias].

Three types of fetal therapy of skeletal dysplasias, as enzyme replacement, in utero stem cell transplantation, and gene therapy, are reviewed. Clinical trial of recombinant ALP for infantile hypophosphatasia has already started in Japan. In future, such enzyme replacement therapy is expected to be adapted to fetus. There are several reports of mesenchymal stem cell transplantation for osteogenesis imperfecta fetus. These case reports have showed that stem cell transplantation is safe and to some extent works in patients. No clinical trial for gene therapy has been reported. Recently, the study of gene therapy of using HPP fetal mouse showed an excellent therapeutic effect. Fetal therapy of skeletal dysplasias is still the stage of research because of the safety and the ethical issues. However, in order to treat severe cases of skeletal dysplasias which abnormal development has been already completed at birth, fetal therapy at an early stage would be demanded.