Why Lupus is Mostly a Woman's Disease
Of the 16,000 cases of lupus -- a chronic autoimmune disease that can damage any part of the body -- that are reported each year in the United States, 90 percent occur in women. Sex differences have long and obviously been suspect as a driving factor, but now scientists think they have a specific culprit: over-expression of a gene called Tlr7.
Tlr7 is found on the X chromosome. Normally in females, who have two X chromosomes, one Tlr7 gene is inactivated as a way to control gene expression -- the genetic instructions issued by that gene. French scientists found that immune cells in female patients with lupus had two functioning copies of the gene, which impacted normal functioning of the cells.
Men with an extra X chromosome have a condition called Klinefelter syndrome. Men with this syndrome develop lupus at much higher rates than other men.
Lupus has been associated with dozens of genes so over-expression of Tlr7 isn't likely to be the sole causative agent, but scientists say if they can find a way to inactivate it on the second X chromosomes, it could produce a measurable therapeutic benefit.
Body of Knowledge
If you took all of the urine the world produces in one day, it would take a full 20 minutes to flow over Niagara Falls.
An Arby's junior roast beef sandwich (126 grams) contains 304 calories, 78 from fat. It has 8.7 grams of total fat or 13 percent of the recommended total fat intake for a 2,000-calorie daily diet.
It also contains 36 milligrams of cholesterol (12 percent); 782 mg of sodium (33 percent); 36.2 grams of total carbohydrates (12 percent); 1.4 g of fiber (6 percent); 4.3 grams of sugar and 17.4 g of protein.
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