Timothy Craig is a doctor of orthopedics and a leading clinical researcher in the field of allergy and immunology. He breaks down how abnormalities in factor XII can lead to recurrent swelling episodes in people with hereditary angioedema, and how modern treatments are helping patients regain control of their lives.
Transcript
People who have an absence of factor XII live normal lives. People who have normal factor XII — which the vast majority of people have — generally don’t have a problem.
Those with a gain-of-function mutation in factor XII are the ones who may fit into that hereditary angioedema with normal C1 inhibitor category. They can have recurrent swelling of their skin, swelling of the abdomen, or swelling of the upper airway.
Also, it’s the activation of factor XII in people with type 1 and type 2 HAE — who don’t have enough C1 inhibitor to shut down that activation — that leads to recurrent swelling, similar to those with the gain-of-function defect.
This leads to increased bradykinin, which causes recurrent swelling of the bowel walls, leading to nausea and vomiting, as well as skin swelling that can be very disfiguring. It can also lead to airway swelling, which could result in asphyxia.
The swelling can last anywhere from two to five days. It’s not just swelling like from a bee sting, which might last a shorter period of time. This swelling can persist for an exaggerated period, and people with severe disease may have swelling up to two times a week.
So you can picture if you’re swelling for three days from an attack and you have two attacks per week — over the course of a year, you’re experiencing a lot of attacks and a lot of disability. You may not even be able to maintain a job.
Now, though, with the medications we have, that’s very, very unlikely because the newer medications are very effective.
