April 17, 2013
Antibiotic Modestly Improves Function, Mood of
Fragile X Children

Sacramento, CA—A readily available antibiotic, minocycline, shows promise in improving function and mood in children with fragile X syndrome (FXS), according to a new study.

Minocycline treatment of children resulted in “modest” but meaningful improvement compared to placebo, according to researchers from the University of California Davis. Often used to treat acne, minocycline is a tetracycline that has been in use since the 1970s.

The study, published by the Journal of Developmental & Behavioral Pediatrics, is important “because minocycline is a targeted treatment for FXS that is currently available by prescription,” according to the authors.

“This study provides evidence of the efficacy of this medication as targeted treatment for fragile X syndrome with a long history of use and that can currently be prescribed,” added lead author Mary Jacena Leigh, MD, associate clinical professor of behavioral and developmental pediatrics with the Fragile X Treatment and Research Center at the MIND Institute. “Further studies examining the long-term benefits and side effects are needed, perhaps in combination with other educational and medication treatments currently being developed for individuals with the condition.”

A result of mutations of the FMR1 gene, FXS is the most common cause of inherited intellectual disability and the most common genetic cause of autism and autism-spectrum disorders. Fragile X syndrome affects about 1 in 4,000 males in the United States, causing intellectual disability and behavioral and learning problems. It also occurs in females but usually results in less impairment.

For the study, researchers randomly assigned 66 children with FXS to 3 months of treatment with minocycline or an inactive placebo, switching them to the alternative treatment for the next 3 months.

On average, the 55 patients who completed the study had small but significant improvements in some areas during treatment with minocycline, compared to placebo, according to the report. Most significant were scores on Clinical Global Impression Scale, where doctors rated their overall impression of the patients’ status. Average scores on the 7-point rating scale were 2.5 points for children taking minocycline versus 3 points for those taking placebo, representing a 0.5-point improvement with minocycline in comparison to placebo.

Minocycline also appeared to improve the children’s anxiety and mood-related behaviors, as rated by parents unaware of who was taking the antibiotic or a placebo. No significant difference was documented with behavior problems, verbal functioning, or other outcomes.

“Some children responded very well to minocycline; others did not, so we now are studying biomarkers that can help us determine who will be a responder,” said Randi Hagerman, MIND Institute medical director and the study’s senior author.

No serious adverse effects occurred, although discoloration of the teeth—a known side effect of minocycline and related antibiotics—was seen in both treatment arms.

Study authors said that more studies “including long term follow up on individuals treated with minocycline are warranted with a careful assessment of side effects and benefits.”

U.S. Pharmacist Social Connect