University of Alberta & St. Justine’s Conduct Study of Metformin in Individuals with Fragile X Syndrome

University of Alberta & St. Justine’s Conduct Study of Metformin in Individuals with Fragile X Syndrome

University of Alberta (Canada) and St. Justine’s Hospital are conducting a controlled trial of metformin in individuals with fragile X syndrome between the ages of 6 and 25 years old. Participants will be randomized in a double-blind design to either drug or placebo and will attend three visits to the study in a four month period for a series of tests. The prime objectives are to assess safety, tolerability, and efficacy of metformin in the treatment of language deficits, behavior problems, and obesity/excessive appetite in individuals with fragile X syndrome.


In this upcoming study, the investigators will examine if a diabetes medicine has behavioral and cognitive effects on children and young adults with fragile X syndrome. Typically, treating fragile X symptoms involves non-pharmacological actions such as speech and occupational therapy. No medications have shown to be effective in treating key symptoms.

Fragile X

Fragile X is a genetic disorder. Symptoms often include mild to moderate intellectual disability. The average IQ in males is under 55. Physical features may include a long and narrow face, large ears, flexible fingers, and large testicles. About a third of those affected have features of autism, such as problems with social interactions and delayed speech. Hyperactivity is common and seizures occur in about 10%. Males are usually more affected than females.

Fragile X syndrome is inherited in an X-linked dominant pattern. Women with a premutation have an increased risk of having an affected child. It is typically due to an expansion of the CGG triplet repeat within the Fragile X mental retardation 1(FMR1) gene on the X chromosome. This results in not enough fragile X mental retardation protein (FMRP), which is required for the normal development of connections between neurons. Diagnosis requires genetic testing to determine the number of CGG repeats in the FMR1 gene. Normal is between 5 and 40 repeats, fragile X syndrome occurs with more than 200, and a premutation is said to be present when an intermediate number of repeats occurs. Testing for premutation carriers may allow for genetic counseling.

The frequency includes 1 in 4,000 males and 1 in 8,000 females. 

Lead Research/Investigator

Francois Bolduc, MD, PhD