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. 
Both medications and surgery have been used to treat ulcerative colitis. However, surgery is reserved for those with severe inflammation and life-threatening complications. There is no medication that can cure ulcerative colitis. Patients with ulcerative colitis will typically experience periods of relapse (worsening of inflammation) followed by periods of remission (resolution of inflammation) lasting months to years. During relapses, symptoms of abdominal pain, diarrhea, and rectal bleeding worsen. During remissions, these symptoms subside. Remissions usually occur because of treatment with medications or surgery, but occasionally they occur spontaneously, that is, without any treatment.