Gene Tampering

In the latest setback for the field of gene therapy, researchers halted trials of a promising program after a french toddler developed a leukemia-like disease that has never before been seen. The child, who was born with an often fatal genetic condition called severe combined immunodeficiency (commonly referred to as "bubble boy" disease), had apparently been cured two years ago when doctors injected him with cells containing the missing normal gene. But gene therapists suspect the replacement gene may have had an unintended effect: disrupting the normal workings of a different, anticancer gene.