Is hereditary angioedema type iii a genetic mutation?

The big unknown: This is a big unknown question, some people have a mutation that can cause type iii and others have an unkown kind that responds to treatments of hae.

Little is known: There have been a subset of patients with hae type iii (now called hae with normal complement) who have a mutation in a blood factor called factor xii. However, this is not the cause in all patients and the exact cause is not yet known.