Description: Two genes boost the risk of painful rheumatoid arthritis, and one of them also increases the odds for lupus, according to two new reports.

In one report, a variant of the gene called STAT4 is one of the five genes now identified to increase the risk of developing rheumatoid arthritis or lupus, both of which are autoimmune disorders, where the immune system attacks healthy tissue.

STAT4 can boost a person's risk for the illnesses by 30 percent to 60 percent, depending on how many copies of the gene one has, the researchers found.

In the other study, a variant of the TRAF1-C5 gene was found to be associated with an increased risk for rheumatoid arthritis.

"There has been a huge amount of optimism about what genetics can bring," said lead researcher Dr. Peter K. Gregersen,