One in 50,000 Americans has HAE, yet laryngeal attacks are just 0.9% of episodes and still drive nearly all its mortality.

Hereditary angioedema is an autosomal-dominant disorder of the SERPING1 gene that leaves C1-esterase inhibitor either too scarce (Type I, roughly 85% of patients) or too dysfunctional (Type II, roughly 15%). The result is unchecked plasma-kallikrein activity and bradykinin overproduction, the mediator behind recurrent, non-itchy swelling that has nothing to do with a typical allergic reaction. US prevalence sits near 1 in 50,000, based on patient-advocacy estimates rather than a peer-reviewed count, and because inheritance is autosomal dominant, every child of an affected parent carries a 50% risk of inheriting the condition.

Symptoms typically begin around age 11 and recur for life. A natural-history cohort of 221 patients tracked 131,110 attack episodes and found cutaneous and abdominal swellings made up 97.4% of them, while laryngeal episodes were only 0.9%, yet they carry essentially all of the disease's mortality risk. Abdominal attacks bring crampy pain, vomiting in 73% of episodes and diarrhoea in 41%, closely mimicking an acute abdomen and often leading to unnecessary surgery before HAE is even considered. Laryngeal attacks kill disproportionately in patients whose disease was never diagnosed, which is why diagnosis, confirmed by a low C4 alongside reduced C1-inhibitor level or function, matters more than any new therapy.

Earlier recognition, not new therapy, is the pivotal commercial and clinical lever.

Five questions this report answers:

Q1 - How large is the US HAE population, and how does the Type I/II split shape the prophylaxis pool?

Q2 - What does the HAE attack burden look like across cutaneous, abdominal and laryngeal attacks?

Q3 - Where is the diagnostic delay in US HAE, and what is the undiagnosed pool worth commercially?

Q4 - How do Type I and Type II HAE differ in C1-inhibitor levels and function?

Q5 - Which HAE attacks are most dangerous, and why do they carry the highest mortality risk?

Share your commercial question with us. We'll align on scope — then build the right intelligence around it.

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Live report page:  https://axlrx.ai/hereditary-angioedema/disease-landscape/

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Mike || Global Pharma Commercial Marketing Head

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