Hereditary angioedema, or HAE, is a life-threatening rare genetic disease with a lot of still-unanswered questions. However, scientists at the Karolinska Institute in Sweden, Science Daily reports, may have answered at least one more: Why does a mutated blood protein factor cause swelling in Type III HAE?
More accurately referred to as “HAE with normal C1INH,” the most rare and least understood subset of HAE.
In people with hereditary angioedema, there is a defect in the gene that controls a blood protein called C1 Inhibitor (C1INH). In HAE Types I and II, there is either not enough C1INH produced or the C1INH doesn’t work as it should. This leads to fluids being released into tissues, causing them to swell.
The swelling from hereditary angioedema attacks in the throat can be shockingly fatal.
The study explains that in a small group of people, mostly women, C1-inhibitor protein levels are normal and appear to be functioning properly, but they still have the swelling episodes characteristic of HAE Types I and II.
Previous research had shown that people with HAE Type III have a mutation in the blood protein factor XII. What researchers couldn’t figure out, Science Daily explains, was why that would cause swellings.
But an HAE study recently published in The Journal of Clinical Investigation offers this exciting new insight: a single sugar was missing in the mutated factor XII, which was found to be overactive. That, in turn, produced an excess of a peptide called bradykinin, which plays a role in increasing fluid leakage through blood vessel walls, causing swelling
Normally, there are natural inhibitors already in blood that prevent factor XII from becoming activated. But these weren’t enough to completely stop the over activation from happening when that single sugar was missing.
In the article by Science Daily, the principal investigator of the study, Dr Thomas Renné, reported that his research team has “previously made an antibody that can inhibit factor XII, and shown that this antibody blocks factor XII driven blood clot formation. In the current study, we demonstrate that the same agent prevents edema in mice.” The team is hopeful that their discovery will lead to new treatment options for those suffering with HAE with normal C1INH levels.
If you are as excited as we are that patients living with hereditary angioedema may finally have an answer to their disease, share this article to spread the news of hope.
