Parents of children with fragile X syndrome reported improvements in their children's attention spans and communication skills as well as decreased anxiety after the children were given the antibiotic minocycline, researchers said Tuesday. The results were strictly observational and were uncontrolled, but they suggest the drug -- which is already used widely for treating teen acne -- might also have a use for the fragile X condition. The results were sufficiently promising that the National Fragile X Foundation is now sponsoring a preliminary clinical trial.
Fragile X is a genetic disorder caused by defects on the X chromosome, one of the cell's two sex chromosomes. It affects about one in 3,600 males and one in 4,000 females in the United States, causing a variety of disabilities that include learning disorders, intellectual impairment and behavioral and emotional problems. It is also associated with certain physical traits, such as prominent ears and unusually flexible finger joints. Symptoms are typically more severe in boys than in girls.
Preliminary studies have shown that minocycline can reduce the damage suffered after a stroke and studies in animals suggest that it can improve neurodegenerative diseases like Huntington's and Parkinson's. Biologist Iryna M. Ethell of UC Riverside and her colleagues have previously shown that minocycline lowers levels of a compound called matrix metalloproteinase 9 (MMP 9) in the brain. MMP 9 inhibits the development of structures in brain cells called dendritic spines, tiny mushroom-like projections at the end of synapses that allow neural cells to communicate. In animal models of fragile X, too much MMP 9 is produced.
In the new study, reported in the September issue of the American Journal of Intellectual and Developmental Disabilities, Ethell, Dr. Randi J. Hagerman, medical director of the UC Davis MIND Institute, and their colleagues prescribed the antibiotic to 53 fragile X patients ranging in age from 4 months to 25 years. Three dropped out because of side effects.
Among the remaining 50 participants, 43 of them male: 54% of their parents said they improved in their use of language; 50% said their children's attention span improved; 44% said their children's social communication improved; and 30% said their children's anxiety decreased. The primary side effects were upset stomachs and a few cases of teeth staining.
Based on the findings, the researchers are initiating a two-year, $100,000 pilot study of the drug in children ages 4 to 16.
-- Thomas H. Maugh II / Los Angeles Times