Acquired complement C1 esterase inhibitor deficiency in a patient with a rare SERPING1 variant with unknown significance

Eva Rye Rasmussen, Kasper Aanæs, Marianne Antonius Jakobsen, Anette Bygum*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Angioedema (AE) is caused by a wide range of diseases and pharmaceuticals; it can become life-threatening when located to the airways. Patients with deficiency or malfunction of complement C1 esterase inhibitor (hereditary or acquired) experience recurrent AE due to an accumulation of the vasoactive mediator bradykinin (BK). Complement C1 inhibitor normally decreases BK production, so a reduced function hereof causes increased levels. The diagnosis of hereditary or acquired AE can be difficult due to similarities to allergic reactions (swelling, abdominal pain, rash). We describe a 35-year-old man presenting with upper-airway AE progressing rapidly and promptly required cricothyroidotomy. Complement and autoantibody screening together with sequencing of SERPING1 were performed and gave the diagnosis of acquired complement C1 esterase inhibitor deficiency. The patient is unusual to have this disease before the age of 40 years. No associated comorbidities were found. It is important to know that antiallergic medication is not effective in BK-mediated AE.

Original languageEnglish
Article numbere231122
JournalBMJ Case Reports
Issue number9
Number of pages5
Publication statusPublished - 1. Sep 2019

Bibliographical note

This article has been accepted for publication in BMJ Case Reports
, 2019 following peer review, and the Version of Record can be accessed online at
© Authors. Reuse of this manuscript version (excluding any databases, tables, diagrams, photographs and other images or illustrative material included where another copyright owner is identified) is permitted strictly pursuant to the terms of the Creative Commons Attribution-Non Commercial 4.0 International (CC-BY-NC 4.0)


  • dermatology
  • genetics
  • immunology


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