Fragile X Syndrome (FXS) is the most common inherited
form of intellectual disability and autism. FXS is due to a loss of a single
gene FMR1, which encodes for the
Fragile X Mental Retardation Protein (FMRP). FXS is characterized by cognitive
disabilities, hyperactivity, and hypersensitivity to sensory stimuli, including
olfactory stimuli. The Fmr1 null
mouse model for FXS, like human patients, lacks FMRP and exhibits many of the
same symptoms as the FXS patients. We
are therefore using this mouse model to explore the cellular and molecular
basis of behavioral olfactory hypersensitivity. Previous data from our lab
suggest that Fmr1 null mice are more
sensitive to odors compared to wild type mice based on their ability to find
hidden food items. To further investigate these differences in odor sensitivity
between Fmr1 null and wild type mice,
we are measuring the responses of both wild type and FXS mice to a series of
increasingly concentrated odors. Since FXS patients find strong odors aversive,
we are asking whether Fmr1 mice
exhibit increased sensitivity and/or abnormal behavioral responses to odorants
that are normally attractive (peanut butter) or aversive (2-methylbutyric acid,
a compound associated with spoiled foods).
