Fragile X syndrome at the turn of the century

Fragile X syndrome is not only the most common form of inherited cognitive impairment, it is also one of the most frequent single gene disorders. It i s caused by a stretch of CGG-repeats within the fragile X gene, which incre ases in length as it is transmitted from generation to generation. Once the repeat exceeds a threshold length, no fragile X protein is produced and di sease results. Since the mutation was discovered, nearly a decade of resear ch has revealed a wealth of information regarding the fragile X gene and it s possible function within the cell. The fragile X story also provides a so bering example of how much time and effort might be necessary to develop be neficial treatment through understanding gene function.