A study led by Michael Akins, PhD, assistant professor of biology at Drexel, shows that the treatment window for Fragile X syndrome likely remains open well beyond childhood, when previous studies indicated it might close. This new information could become valuable as therapeutic treatments for Fragile X syndrome — the most common autism-related disorder.
The team found structures called Fragile X granules in the hippocampus (the part of the brain that controls memory) well into maturity in both rat and human specimens. These granules, which Akins helped discover in 2009, are thought to contribute to Fragile X syndrome when they become decoupled from a gene called the Fragile X mental retardation protein, or FMRP.
Fragile X syndrome affects roughly 1 in 4,000 males and 1 in 6000 females.
While Fragile X granules were found in the brains of adult rats and humans, they seemed to disappear in the brains of mice when they reached maturity. As a result, most previous studies would have missed the evidence of these granules in adulthood because the studies focused on mice.
Finding that Fragile X granules linger in the hippocampus of adult humans could expand the age range for treatment. In Akins’ study, one human brain sample from a 57-year-old person showed evidence of the granules, suggesting that treatment could be applied into adulthood.
The team also found that treatment may need to target the nerve cells that house FMRP and Fragile X granules more any broadly.
Akins and colleagues found that FMRP in axons, which are the information transmitters in neurons, shares some unexpected similarities to the FMRP in dendrites, which are the information receivers and the focus of most research. This means that therapies that target those similarities might fill in for the lost FMRP in both parts of the cell.
“We’re still trying to understand what the FMRP is doing in the axons — and how its absence from axons contributes to Fragile X — but this is a major step forward,” Akins says. “We have some new leads.”