For a long time, mental retardation was believed to be incurable, as it is usually caused by gene mutations that disrupt brain development right from the beginning and even before birth. But thanks to a lot of hard-working scientists, there are trials now to improve the quality of life of such patients, along with their caregivers. The work has been focused on a condition known as “Fragile X syndrome”. In this disease, a mutation takes place in a gene called FMR1 , which is responsible for the production of proteins, that regulate neural development, usually leading to mental retardation according to the extent of such mutations.
Another important contributor to the condition is the metabotropic glutamate receptor-5, abbreviated to mGluR5. It is responsible for controlling the process of protein synthesis at the neuronal synapses, becoming hyperactive in case of fragile X. Being an interesting therapeutic target, a major pharmaceutical company developed AFQ056, an mGluR5-receptor blocker, in the hope that it’ll restore normal transcription levels. The results of the initial double blind clinical trials, conducted on 30 patients, were evaluated through the notes taken by the caregivers about the behavioral improvements of the patient. This included less repetitive behavior, less hyperactivity, less tantrums and having better chances of establishing communication with the patients.
What seemed like a puzzle is that some caregivers reported no change at all after the patients took the drug. So after data analysis, the researchers found that the only patients affected by the treatment were the ones (7 patients out of 30) having a certain genetic marker: complete methylation of the FMR1 gene regulator sequence, and therefore, complete lack of FMR1 transcription. Another disappointment was that the drug didn’t improve cognition or memory, but this, they say, might be attributed to the short duration of the trial, lasting for only 4 weeks.
The next step is to repeat the trial, but this time on 160 selected patients, after testing them for the marker and the experiment will last for 3 months, hoping to obtain better results that are more significant to the patients of this illness.AFQ056, FMR1, fragile X syndrome, mental retardation, metabotropic Glutamate receptor 5 blockers, mGluR5-receptors