Pattern of chemical tags on DNA linked to the autoimmune disease
Lupus can tell identical twins apart by the distinguishing marks the pairs carry on their DNA.
Fewer DNA methylation marks may leave one twin vulnerable to the inflammatory autoimmune disease, even while the other sibling remains healthy, a new study appearing online December 22 in Genome Research shows.
The finding suggests that environmental factors determine whether genetically susceptible twins will contract lupus, or systemic lupus erythematosus, which is characterized by the immune system attacking the body’s own cells.
Researchers have previously identified at least 17 different genes involved in lupus. If genes alone were responsible for determining whether a person gets lupus, then every time one identical twin got the disease, the other should too.
But that doesn’t happen. Between 40 percent and 75 percent of the time, when one twin develops lupus the other stays healthy, indicating that some environmental facto