In a typical example of international research, a team of scientists from USA (MIT), India (Tata Institute of Fundamental Research and National Instiute of Mental Health and Neurosciences), and Korea (Seoul National University) have annoounced that they have been able to reverse the effects of mental retardation in specially bred mice.They predict that we can expect similar results in human beings in five years.
Fragile X Syndrome (FXS), which is the leading inherited cause of mental retardation and the most common genetic cause of autism is linked to a mutated X chromosome gene called the fragile X mental retardation 1 (FMR1) gene; when mutated this gene can cause anything from mild learning disabilities to severe autism.
According to Wikipedia: Fragile X syndrome is a syndrome of X-linked mental retardation. Boys with the syndrome may have large testes (macroorchidism), prognathism, hypotonia and autism, and a characteristic but variable face with large ears, long face, high-arched palate, and malocclusion. Additional abnormalities may include lordosis, heart defect, pectus excavatum, flat feet, shortening of the tubular bones of the hands, and joint laxity. Females who have one fragile chromosome and one normal X chromosome may range from normal to mild manifestations of the fragile X syndrome. The fragile X syndrome has an estimated incidence of 1 in 3600 males and 1 in 4,000-6,000 females.
The FXS mice showed abnormalities similar to those in FXS patients, including hyperactivity, purposelessness, repetitive movements, attention deficits and difficulty with learning and memory.
The scientists found that When the enzyme P21-activated kinase (PAK) was inhibited with the FXS mice, electrical communication between neurons in the brains of the mice were restored and their behavioral abnormalities were corrected.
The researchers suggest that by inhibiting PAK the debilitating symptoms of FXS in children could also possibly be countered.The Indian contribution to the research involved monitoring how the neurons in the brain were altered in the mentally challenged.
Co-author Susumu Tonegawa, a Picower Professor of Biology and Neuroscience at MIT says the results were intriguing because it suggests that PAK inhibitors could be used for therapeutic purposes to reverse already established mental impairments in fragile X children - thus holding out a ray of hope for the millions living with mental retardation.
The Indian authors in the study are B. S. Shankaranarayana Rao (NIMHANS) and Sumantra Chattarji (TIFR). Other scientists involved in the study are Mansuo L. Hayashi, Jin-Soo Seo, Han-Saem Choi, Bridget M. Dolan and Se-Young Choi.