Family history is a risk factor for asthma, with many different genes being implicated. If one identical twin is affected, the probability of the other having the disease is approximately 25%. By the end of 2005, 25 genes had been associated with asthma in six or more separate populations, including GSTM1, IL10, CTLA-4, SPINK5, LTC4S, IL4R and ADAM33, among others. Many of these genes are related to the immune system or modulating inflammation. Even among this list of genes supported by highly replicated studies, results have not been consistent among all populations tested. In 2006 over 100 genes were associated with asthma in one genetic association study alone; more continue to be found. COUNT 5
QSN1 What else is a risk factor for asthma? ANS1 Family history QSN2 If one identical twin has asthma, what are the odds of the other twin having asthma? ANS2 approximately 25% QSN3 How many genes were associated with asthma by the end of 2005? ANS3 25 genes QSN4 How many genes were associated with asthma in 2006? ANS4 over 100 genes QSN5 What else are these genes closely related to? ANS5 the immune system or modulating inflammation