Then last month two teams of researchers reported in the journal Science that they had discovered the site of the mutation. And last week geneticists reported in Cell that they had pinpointed the actual gene responsible for the syndrome. “We know what we are dealing with for the first time,” says Prof. Steven Warren of Emory University School of Medicine, principal author of the study.
Fragile X is named after a mutation of the X chromosome, the tip of which under a microscope sometimes appears to hang by a thread. The defective gene is located within that “fragile” site. The Fragile X gene may produce a faulty protein unable to carry messages among brain cells. That would cause impaired mental functioning. “But it’s too soon to tell,” cautions David Nelson of Baylor College of Medicine.
No treatment is yet possible, but families with histories of mental illness can have genetic testing for evidence of Fragile X. Says Nelson, “It’s the best diagnostic tool you can imagine.”
