HAE is a very rare but serious condition. It affects somewhere between 1 in 30,000 and 1 in 50,000 people. It causes attacks of swelling on different parts of the body, usually associated with abdominal problems (issues in the tummy).
How it Happens
There are three main types of HAE. They are mostly due to a problem with a protein that prevents the leakage of fluids to the tissue. This protein in the body is called C₁-esterase inhibitor (C₁-INH). This problem is usually a result of something genetic. It causes the protein to not be made in enough amounts or makes the protein not work well. Also, parents with HAE should know that there is a 50 percent chance they will pass it on to their children.
However, saying that HAE seems to come from a genetic problem doesn’t mean it has to run in the family. Sometimes, the problem with the gene happens only to the person affected by HAE. This is called a spontaneous mutation of the gene.
Although C₁-INH (C₁ inhibitor) has other functions related to the immune system and blood clotting, these don’t seem to be affected in HAE.
