Research suggests that people probably develop vasculitis because of the complex interaction of their genetic inheritance, which may increase the risk of developing vasculitis, and exposure to chemicals in the environment or possibly some types of infection (including hepatitis B virus) which may trigger the vasculitis in someone who is susceptible. This does not mean that vasculitis can be inherited or passed on to children.
The immune system is controlled by many thousands of different genes and it is probable that there needs to be some variation in several different genes in combination to make an individual more “at risk” of vasculitis than others. This does not mean that the genes do not work just that they may work slightly differently.
For example, a red apple and a green apple are both apples but they are slightly different. In the same way a single gene may have slightly different variations in different people but still be the same gene doing pretty much the same job. Several genes have been identified where one variety is more common in people with vasculitis and other types of autoimmune disease. This does not mean that the gene caused the vasculitis as many people with the “vasculitis” variety of gene never get vasculitis and some people with the “not vasculitis” version of the gene do get vasculitis. The variety of gene may not even be specific to one type of vasculitis but may be affecting the way the immune system responds to infections, chemicals or toxins.