another random user writes
"According to the BBC, 'Europe is on the cusp of approving a gene therapy for the first time, in what would be a landmark moment for the field. ... The European Medicines Agency has recommended a therapy for a rare genetic disease which leaves people unable to properly digest fats. The European Commission will now make the final decision. The idea of gene therapy is simple: if there is a problem with part of a patient's genetic code then replace that part of the code. The reality has not been so easy. In one gene therapy trial a U.S. teenager, Jesse Gelsinger, died, and other patients have developed leukaemia. There no gene therapies available outside of a research lab in Europe or the U.S.' They have considered the use of Glybera to treat lipoprotein lipase deficiency, which leads to fat building up in the blood, abdominal pain and life-threatening pancreatitis (inflammation of the pancreas). 'The therapy uses a virus to infect muscle cells with a working copy of the gene.'"