HAE day :-) May 16th

Today is HAE (hereditary angioedema) Day :-)

A bit about HAE:

Hereditary Angioedema is a blood and immune disorder, there are 3 types.

Types 1 and 2 are both also known as C1 inhibitor deficiency, with type 1, there is a genetic mutation which leads to not enough C1 inhibitor being produced. With type 2 there is also a genetic mutation in the same gene, but normal or even high levels of C1 inhibitor are produced, but some of the protein that is produced doesn't function normally. In both cases, it's inherited in an autosomal dominant fasion, so if someone with hereditary angioedema has a biological child with no intervention, there's a 50% chance the child will also have hereditary angioedema. Although it is a genetic disorder, 20-25% of the time it's a new mutation, so not everyone who has one of these types will have a parent who is affected. It is not possible to be a carrier for types 1 and 2 without having the condition though, but the severity does vary from one person to the next.

There are also other causes of hereditary angioedema - various other genetic mutations that tend to be further down along one of the pathways that c1 inhibitor works one. Some of these have been identified but there's an expectation that at least one is not. These used to be called to as type 3 HAE, and many still will refer to type 3 for simplicity, but the official diagnosis is now normal c1 inhibitor hereditary angioedema, which can be abbreviated as nC1inh HAE. Some of the old information on type 3 suggested that it was hormone depedent and mostly affect women who are menstruating, are pregnant or utilizing hormonal contraceptives or hormone replacement therapy. It's possible some specific mutations also require an environmental factor such as hormones, but it's now known this isn't true for all instances of nC1inh HAE.

All of these types of HAE lead to one thing - too much bradykinin. Bradykinin increases the permeability of blood vessles and during a hereditary angioedema attack fluid leaves the blood and enters into surrounding tissue that it creates swelling, and this can be severe. Some common sites for HAE attacks include the limbs, the face, the abdomen/intestinal tract, the urinary tract, the genitals and the throat/airway. All attacks involving the airway should be considered medical emergencies, as these can lead to asphixation and the mortality rate without treatment is 30%. Abdominal attacks can also be fatal due to the loss of fluid from the blood as well as complications such as intussusception.

Other things to check out:

I have heredtiary angioedema AMA

Importance of HAE treatments

Upcoming - Mental Health & Rare Disorders