People who have two or more siblings who have suffered blood clots in deep veins such as those in the legs and pelvis -- a disease known as venous thromboembolism (VTE) -- have a relative risk 50 times higher for developing such clots themselves, Swedish researchers report. Individuals with only one sibling with VTE are two times as likely to suffer the dangerous blood clots. This is the first study in a large population to show that the risk for VTE runs in families, the researchers say. VTE causes blood clots called deep vein thrombosis, which, if they break loose, can travel to the heart, lungs or brain and, if untreated, tend to be fatal.
