A large genetic study confirmed that Arabs share a rheumatoid arthritis risk gene with other populations, but identified new genes that may be involved in triggering the disease in Arabs and not in Europeans and Asians.
The study, “A multi-national Arab genome-wide association study identifies new genetic associations for Rheumatoid Arthritis,” was the first large-scale attempt to investigate the genetic risk of rheumatoid arthritis among Arabs.
The work, which involved patients and controls in five countries, was published in the journal Arthritis & Rheumatology.
“This research, funded by the Qatar National Research fund, is one of the largest studies ever conducted among Arabic populations with Rheumatoid Arthritis,” Dr. Thurayya Arayssi, the study’s senior author, said in a press release. She is with Weill Cornell Medicine-Qatar,
“The results of the study give us new and extremely valuable population-specific insights into the pathophysiology of rheumatoid arthritis, which is extremely encouraging. RA [rheumatoid arthritis] is a very unpleasant disease to live with, so any discoveries we can make about it are very valuable and could help future researchers develop new, more effective drug therapies.” Arayssi said.
The Weill Cornell team and researchers at the Broad Institute in Massachusetts worked together on a genome-wide association study (GWAS). They also analyzed about 1,600 patients and controls from Qatar, Jordan, Saudi Arabia, Lebanon and the United Arab Emirates.
As with other populations, the team found that a gene called HLA-DRB1 was linked to rheumatoid arthritis in Arabs. They also found two other regions — intergenic 5q13, 17p13 at SMTNL2/GGT6 — that were linked to the disease in Arabs but not in Europeans or East Asians.
“Arab populations are diverse, and as in other populations, family history is an important risk factor for rheumatoid arthritis in Arabs. Before this study, little was known about the specific genetic factors underlying RA risk in this ethnic group,” said Dr. Richa Saxena of the Broad Institute, the study’s first author.
“As expected, we found that dozens of genes already known for RA from European and Asian populations also play an important role in Arabs. Surprisingly, we also found two new genetic factors that increase risk of RA in Arabs only but do not influence risk in these other populations,” Saxena said. “Biological and clinical follow-up studies on known and new genes will improve understanding of the causes of RA, and allow for better risk assessment in Arabs and opportunities to develop new RA therapies.”
“This multicenter and multination regional study, which included international collaborations, illustrates the power of global collaborative science and the impact it can have on a better understanding of diseases in Qatar and the region,” added Dr. Khaled Machaca, associate dean for research at Weill Cornell Medicine-Qatar.