BEIJING, Jan. 21 (Xinhuanet) -- It has long been suspected that both genetic and environmental factors are at play in lupus casuing the immune system to mistakenly attack organs in the body.

    Researchers in U.S, Europe and Scandinavia have now explained partially the causes of the disease by four studies in the journal Nature Genetics and the New England Journal of Medicine as quoted by media reports Monday. 

    Last month, a variant of a gene called TNFSF4, also on Chromosome 1, was described by researchers as boosting the risk of lupus.

    In the current studies, they have identified six more gene variants that boost the risk of developing lupus from 25 to 200 percent.  

    Separately or together, the six play a part in the molecular pathway of systemic lupus erythematosus (SLE). 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.

    In the studies, about 10,000 people were tested and 13 different genes implicated. Researchers tested the DNA of more than 6,700 women, including people with lupus, their relatives, and unrelated people with no evidence of the disease. 

    Women are at much higher risk of the disease, and are often diagnosed during their childbearing years, the studies found.

    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, they added.

    Scientists suggested the next step is to figure out what these genes are doing and whether something in the environment, such as a virus or a pollutant, is switching them off or on.

    (Agencies)