Switching off faulty genes can cure brain diseases
Incurable disorders like Huntington's and Alzheimer's can be treated by disabling the flawed genes and leaving the healthy ones unharmed, find scientists.health and fitness Updated: May 27, 2003 18:47 IST
Scientists have taken a step further in treating inherited diseases by switching off defective genes, leaving healthy genes unharmed.
Incurable illnesses such as Huntington's disease and other disorders of the brain and nervous system could eventually be treated by the technique, according to a report in The Independent.
The researchers have demonstrated the treatment, using the revolutionary process of RNA interference. RNAi has become the hottest topic in medical science since scientists showed last year that it can destroy damaged or defective genes in human cells almost at will. Last December, RNAi was voted "breakthrough of the year".
The latest research was done on genetically defective human cells in a test tube. The scientists believe the findings are a powerful demonstration that RNAi could also be used on real patients suffering any of the many thousands of inherited disorders, the report said.
Henry Paulson, of the University of Iowa, who led the research, said the study was aimed at seeing whether RNAi was powerful enough to turn off diseased genes even when they were "dominant", meaning that inheriting just one defective copy from a parent always resulted in the illness.
The research investigated RNAi's gene-silencing power on human cells affected by mutations causing Machado-Joseph disease, an illness of the brain and spinal cord, and a genetic form of Parkinson's disease, the report noted.
Scientists did not understand precisely how any of those toxic disease genes caused brain cells to become sick and die, but it seemed clear that eliminating the toxic gene product - the bad protein - would be ideal.
The research also shows how precise the RNAi technique is. It distinguished between the healthy and diseased version of the same gene, though they differed by only a single change in the DNA sequence of chemical bases or "letters", the report added.