How does permanently modifying human DNA work? And how does it impact procreation?
It seems this therapy is targeted to liver cells. Cells that are affected will continue to express the inserted gene as long as they last, and any dividing cells will spread it to their daughter cells.
Genetic information is passed on to the next generation through germline cells: eggs and sperm. There won't be any effect on the next generation unless these cells or the cells that give rise to them have the inserted gene.