Genetic defect tied to autoimmune diseases
Rare mutations lead to several different disorders
Rare variations in a single gene can lead to a wide variety of autoimmune disorders, including diabetes, lupus and rheumatoid arthritis, a new study shows.
The gene in question encodes an enzyme called sialic acid acetylesterase or SIAE, which regulates the activity of the immune system’s antibody-producing B cells. About 2 percent to 3 percent of people with autoimmune disorders have defects in the enzyme that allow B cells to run amok and make antibodies that attack the body, a team led by Shiv Pillai of Massachusetts General Hospital in Charlestown and Harvard Medical School reports online June 16 in Nature.
“It’s a seminal paper because it is so applicable to a wide variety of autoimmune diseases, says Judy Cho, a Yale geneticist not associated with the study. The finding suggests that enhancing the enzyme’s activity could help treat disease in people with autoimmune disorders.
Previously, Pillai’s group showed that mice lacking SIAE develop a lupuslike disease in which high levels of antibodies attack the body’s own proteins. The researchers decided to examine the enzyme in people who, like the mice, make high levels of autoimmune antibodies. “One hundred percent, I was confident that we would find nothing,” Pillai says.