Scientists reported Thursday the discovery of a simple test for the most common inherited form of mental retardation, providing a tool for determining whether parents or unborn children carry the defect.
Two versions of the test, developed in France and Australia, can detect a mutant gene that causes fragile X syndrome. Neither test is available for routine use.If they turn out to be as accurate as experts believe, the tests could allow doctors to counsel parents in families with a history of the syndrome. Parents would know whether they risked passing on the defect, and they could learn whether their unborn children were likely to be mentally retarded or to be carriers of the defect.
The tests also could help doctors understand whether the genetic mixup was responsible for unexplained cases of autism, hyperactivity and retardation.