This is a single center study at the UC Davis MIND Institute in patients age 3.5-16 years of
age with fragile X syndrome (FXS), funded by a National Fragile X Foundation Grant. It is a
controlled trial of minocycline, an antibiotic commonly used in children for infection or for
treatment of neurodegenerative disorders. We are investigating its use in FXS because it
lowers matrix metalloproteinase 9 (MMP9) levels, which are high in FXS, and it also
strengthens brain connections in the animal models of FXS. We hypothesize that minocycline
will likely be helpful for language, behavior and/or cognition in fragile X patients.