HAE Causes: A Handful of Genetic Changes
HAE occurs as a result of a genetic change. The mechanism of an HAE attack varies depending on which genetic change you have.
There are known mutations in the SERPING1 gene and a few other genes. Scientists suspect there are also other as yet unidentified genes that cause HAE. Which genetic change you have may influence the type of treatment your doctor prescribes.
Changes in the SERPING1 Gene Cause HAE Type 1 and 2
Changes in the C1NH gene, also known as the SERPING1 gene, cause type 1 and type 2 HAE.
The SERPING1 gene tells the body how to make a protein called C1-INH, which is important for controlling swelling. In type 1 HAE, your body does not make enough C1-INH protein. With type 2, your body makes enough of the protein, but it doesn’t work properly.
Without normal and functional amounts of C1-INH protein, the body generates too much bradykinin, a protein peptide. Bradykinin causes excessive fluid to leak through the walls of blood vessels, which leads to inflammation and episodes of swelling.
Genetic Changes That Cause HAE With Normal C1-INH Levels
This type of HAE is an extremely rare form of the disease. Its exact prevalence isn’t known. Scientists believe changes in the F12 gene cause this type.
In this type of HAE, C1-INH protein levels and functioning are normal, but the F12 changes cause dysregulation in the bodily system that makes a protein called coagulation factor XII. This protein plays a role in stimulating inflammation and producing bradykinin.
Variants in several other genes are currently thought to be implicated in HAE with normal C1-INH protein levels. Other cases have no known causes and could be due to variants that haven’t yet been identified.
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