Researchers at the University of Minnesota Medical School have discovered the gene responsible for a type of ataxia, an incurable degenerative brain disease affecting movement and coordination.
This is the first neurodegenerative disease shown to be caused by mutations in the protein b-III spectrin which plays an important role in the maintaining the health of nerve cells. The scientific discovery has historical implications as well--the gene was identified in an 11-generation family descended from the grandparents of President Abraham Lincoln, with the President having a 25 percent risk of inheriting the mutation.
"We are excited about this discovery because it provides a genetic test that will lead to improved patient diagnoses and gives us new insight into the causes of ataxia and other neurodegenerative diseases, an important step towards developing an effective treatment," said Laura Ranum, Ph.D., senior investigator of the study and professor of Genetics, Cell Biology and Development at the University of Minnesota.
Understanding the effects of this abnormal protein, which provides internal structure to cells, will clarify how nerve cells die and may provide insight into other diseases, including amyotrophic lateral sclerosis (Lou Gehrig's disease) and Duchenne muscular dystrophy. The research will be published in the February print issue of Nature Genetics, and posted online Jan. 22, 2006.
Ataxia is a hereditary disease that causes loss of coordination resulting in difficulty with everyday tasks such as walking, speech, and writing. About 1 in 17,000 people have a genetic form of ataxia.
Spinocerebellar ataxia type 5 (SCA5) is a dominant gene disorder; if a parent has the disease, each of their children has a 50 percent chance of inheriting the mutation and developing ataxia sometime during their lifetime. The onset of SCA5 usually occurs between the ages of 30 and 50, but can appear earlier or later in life, with reported ages of onset ranging from 4 to more than 70 years of age.