Investigators reported on Sunday they had identified six more gene regions associated with the severest form of lupus, a complex autoimmune disease that mainly strikes women.
Lupus causes human antibodies -- the frontline troops in the defence system -- to attack the body's tissues, resulting in inflammation that is often mild but in extreme cases can be life-threatening.
The variants of half a dozen genes are described in four studies published in Britain's Nature Genetics and the New England Journal of Medicine, headquartered in the United States.
Separately or together, the six play a part in the molecular pathway of systemic lupus erythematosus (SLE), a chronic form of lupus that can affect skin, lungs, blood vessels, the brain and nervous system.
The six are ITGAM, located on Chromosome 16; BLK, on Chromosome 8; KIAA1542, on Chromosome 11; rs10798269, on Chromosome 1; PXK on Chromosome 3; and BANK1, on Chromosome 4.
The variants were netted thanks to a comparison of the genes of thousands of individuals, most of them women. Ninety percent of lupus patients are female.
Last month, a variant of a gene called TNFSF4, also on Chromosome 1, was described as boosting the risk of lupus.
As yet, there is no cure. Treatments focus mainly on dealing with the inflammation.
Identifying genes that are linked to a disease can be helpful in several ways.
People who are identified as being at risk can be advised on making lifestyle choices that avoid triggering the disorder, and pharmaceutical engineers are offered genetic targets for drugs that block or ease the disease process.