In a research study spanning over three decades, scientists found that DNA repair genes may determine when the neurological symptoms begin in Huntington’s disease. Huntington’s disease is an inherited disorder of the brain in which cells in certain parts of the brain degenerate and die. It is caused by changes in a gene that encodes the Huntingtin protein. Symptoms usually begin between the ages of 30 and 50, but can appear in senior citizens and children too.
The results of the current study, which involved analyzing the chromosomes of more than 4,000 Huntington’s patients, can not only provide a guide for discovering new treatments for Huntington’s disease, but also serve as a guide for studying other neurological disorders.
James Gusella, director of the Center for Human Genetic Research at Massachusetts General Hospital (MGH) and the author of the study hopes that the clinically-proven genetic factors they discovered will help find ways that can slow or delay the onset of the devastating symptoms of Huntington’s disease.
The full details of the study are published online in Cell.
For this study, the scientists already knew the disease-causing gene and so they used the Genome Wide Association Study analysis techniques to search for other changes that determine when the disease starts. They found that at least three sites were associated with symptoms appearing earlier or later than expected, one on chromosome 8 and two on chromosome 15.
According to Margaret Sutherland, program director at the National Institute of Neurological Disorders and Stroke, this could have a significant impact on Huntington’s disease patients.
The study was conducted by the Genetic Modifiers of Huntington’s Disease Consortium, an international team of scientists devoted to finding treatments for the disorder. The scientists used DNA and clinical information, collected for more than 30 years from patients in United States, Canada and Europe to study the age when movement problems began.
Although the scientists did not identify specific genes, they used several types of genome network analyses to show that disease onset may be controlled by genes that assist with the division of mitochondria, genes that repair DNA, and genes that catalyze essential chemical reactions in cells.
Finally, the scientists showed that the sites on chromosomes 15 and 8 may be associated with the beginning of the symptoms of the disease.
These results will help us understand how nature has learned to modify the disease-causing effects of Huntington’s disease changes said researchers. The next step, they said, is to study more patients.