reversing fragile x 03/09/07. By the Wellcome Trust Research reveals a potential target for the treatment of fragile X syndrome.

Fragile X syndrome is the leading genetic cause of mental retardation and autism in humans, but there is no effective means to treat it. Now though, research in mice suggests that fragile X could be reversed.

In the brain, neurons receive signals from synapses via protrusions called dendrites. Dendrites themselves are lined with dendritic spines, which are vital for communication between neurons. People with fragile X syndrome tend to have more dendritic spines than those without, but these spines are longer and thinner, and transmit weaker electrical signals.

A team from the USA, India and South Korea found that blocking the activity of an enzyme called p21-activated kinase (PAK) not only restored the structural abnormalities and electrical connections in the brains of the mice, but also improved behavioural symptoms, including hyperactivity and purposelessness.

Chemical PAK inhibitors are already known, and could be useful in developing drugs to treat fragile X syndrome. Interestingly, inhibiting PAK had an effect on impairments that were already established in the mice, suggesting that future human treatments could still be effective after symptoms have become pronounced.

References

Hayashi ML et al. Inhibition of p21-activated kinase rescues symptoms of fragile X syndrome in mice. Proc Natl Acad Sci USA 2007;104(27):11489-94. Abstract ; full text