Defective gene behind arthritis, diabetes: Study
TORONTO - Scientists at Mount Sinai Hospital identified a defective gene which can spur the development of rheumatoid arthritis, diabetes, lupus and other autoimmune diseases.
After five years, researchers have figured out how the mutant gene PTPN22 increases the risk for rheumatoid arthritis, type 1 diabetes, lupus, Graves disease and other autoimmune disorders.
“Our findings are particularly exciting because the study sets a new precedent for studying arthritis and other autoimmune disorders,” said Dr. Katherine Siminovitch, a senior investigator at the Samuel Lunenfeld Research Institute at Mount Sinai Hospital and a University of Toronto professor.
Simonovitch and her team found the gene — which normally produces a protein that suppresses immune cell responses — changes to the point where this protein nearly vanishes and the immune response becomes too strong and starts attacking its own good cells.
Using a genetically modified mouse model, Siminovitch and her team were able to mimic the genetic defect found in many rheumatoid arthritis patients. After the effects of the missing protein and strong immune response was seen in mice, the researchers repeated the test in human blood samples from patients with and without rheumatoid arthritis.
The team found the defective gene led to decreased levels of Lyp/Pep. In healthy cells, Lyp/Pep prevents hyper-immune responses which lead to autoimmune disorders.
This study opens the door for researchers to measure the levels of this protein to help monitor disease severity in patients with autoimmune disorders, test the effects of various new drugs and determine which treatments work best.
The study is published in scientific journal Nature Genetics.