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. 
The most common side effects associated with fluticasone are headache , throat infection, nasal irritation, sneezing , cough , nausea , vomiting . Hypersensitivity reactions such as skin rash , itching , facial swelling, and anaphylaxis may occur. Some children may experience growth suppression when using fluticasone. A bloody nasal discharge ( nosebleed ) and septum perforation may occur. Fungal infection of the nose and throat, glaucoma , and cataracts are also associated with intranasal fluticasone.