Examining Physiology and Brain Function in People With the Fragile X Premutation
Condition: Fragile X Premutation
Study type: Observational

Summary: 
      This study will examine whether individuals with the fragile X genetic premutation are likely
      to have emotional, social, and memory deficits and how the brain may be involved in these
      deficits.
    

Detailed description: 
      FMR1 is a gene associated with fragile X syndrome-the most common cause of mental
      retardation-and with social, emotional, and cognitive deficits. The chance of developing
      these deficits depends on the number of times the FMR1 gene is repeated on the X chromosome.
      Individuals with more than 200 copies of the FMR1 gene have the full fragile X mutation,
      putting them at most risk for mental retardation. Individuals with between 55 and 200 copies
      of the FMR1 gene have the fragile X premutation; they are much less likely to develop mental
      retardation, but they may have subtle social, emotional, and cognitive deficits and their
      children are more likely to have the full fragile X mutation. A theory, which this study will
      test, holds that the deficits of people with the fragile X premutation are caused by
      dysfunction in the limbic system. The limbic system consists of a group of structures in the
      brain that govern emotions and behavior. This study will examine people with the fragile X
      premutation to determine whether and to what extent they have emotional, social, and memory
      deficits. The study will also determine whether changes in fragile X gene function are
      related to increased deficits and how the brain, and specifically the limbic system, may be
      involved in these deficits.

      Participation in this study will last 2 days. Participants will undergo several hours of
      testing at a lab on back-to-back days. Testing on the first day will include the following:
      providing several saliva samples; undergoing neuropsychological testing, in which
      participants will solve different types of problems and be interviewed about their emotional
      and social experiences; and undergoing a physical exam and blood draw.

      Testing on the second day will include the following: an MRI scan, which will take pictures
      of the brain both while participants are resting and while they are performing certain tasks;
      more neuropsychological testing similar to that from the day before; and questionnaires about
      emotional and social experiences. A family member will also be asked to fill out a
      questionnaire about the participant. On 2 other days, participants will be asked to collect
      saliva samples while at their homes and send the samples to the study researchers. In
      addition, the researchers will keep in contact with participants in case any follow-up is
      needed over the next few years.
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Members of the general population, those with the fragile X premutation, and the brothers
        of those with the fragile X premutation
      
Biospecimen description: 
      Saliva and blood samples
    
Keywords: Fragile X Premutation; FMR1; Premutation; Fragile X; Brain Function