Enlarge Image Gene fix. Red cells in this slice of mouse liver are making a human protein called A1At. Credit: K. YUSA ET AL., NATURE (ADVANCED ONLINE EDITION) ©2011 MACMILLAN PUBLISHERS LTD. Researchers have taken a step toward showing how stem cells might one day be used to help patients born with a deadly liver disease. The researchers corrected a DNA spelling error in patient skin cells that had been converted into so-called induced pluripotent stem (iPS) cells, then coaxed the cells to form liver cells that seemed to function normally in mice. The approach is still a long...