Researchers Find an Area of the Brain Linked to Fragile X Syndrome

A team of researchers from India’s National Centre for Biological Sciences (NCBS) and New York University’s Center for Neural Science has identified novel synaptic defects in an area of the brain that is involved in the emotional symptoms of Fragile X Syndrome.

Sumantra Chattarji, a professor at NCBS, and Aparna Suvrathan, a graduate student, determined that defects existed on both sides of synapses in the amygdala. Eric Klann, an NYU professor, and Charles Hoeffer, a former postdoctoral fellow in the Center for Neural Science who is now enrolled in the NYU School of Medicine, “identified the molecular correlates of these defects, giving the researchers a firm understanding of where the breakdown occurs.” Together, these two findings have identified the deficits that “impair the ability of neurons in the amygdala to communicate and encode information.”

The researchers then examined the impact that these findings could have in regard to Fragile X Syndrome, focusing on group I metabotropic glutmate receptors (mGluRs), which are known to be involved in synaptic dysfunction in other brain areas in Fragile X Syndrome. The investigation revealed that “some of the synaptic deficits could be reversed when the amygdala neurons in adult FXS model mice were treated with a drug that blocks these receptors.” Blocking the ability of these receptors to function properly allowed normal communication between neurons to occur.

“Our results suggest that synaptic defects in the amygdala of knockout mice are still amenable to pharmacological interventions against mGluR5, albeit in a manner not envisioned in the original hippocampal framework,” the researchers wrote in PNAS.

Because Fragile X Syndrome arises in early childhood, the results of the study may reveal that synaptic defects can be corrected pharmacologically, even after the syndrome has had time to impact the brain of an individual, according to the researchers. They add that these new findings “follow recent reports that pharmaceutical companies have conducted clinical trials in FXS individuals using compounds that block mGluRs.”