Flawed Stem Cells Yield Fragile X Clues: Researchers study genetic disorder via discarded embryos

Scrutinizing the first days of development in abnormal embryonic stem cells, researchers have uncovered a basic mechanism underlying fragile X syndrome, the most common inherited cause of mental retardation in boys.

“It could have important implications for treatment,” says W. Ted Brown, cochair of the scientific committee of the National Fragile X Foundation, which helped fund the work.