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Forty Years of Knowing How

Replacing C1-INH plasma protein gives a rare disease a longed-for treatment.


Many people who have rare diseases yearn for a diagnosis – to give their symptoms a name and have a path forward. Too often with rare diseases, medical experts have no treatment to offer.

So it was until 1979 for patients who have hereditary angioedema (HAE), an inherited condition that causes dangerous swelling attacks. HAE is primarily caused by missing or low levels of the plasma protein C1 esterase inhibitor (C1-INH).

This year, we celebrate the 40th anniversary of a milestone for HAE patients: That the absent plasma protein could be replaced through C1-INH therapy, reducing the likelihood of attacks. This timeline reviews how more than a century of research advanced the science and improved patients’ lives.

40th anniversary C1 timeline