HAE UK is an Association of HAE Patients, working together to improve the situation for all HAE Patients in the UK
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More HAE information

HAE patients have a defect in the gene that controls a blood protein called C1 Inhibitor. C1 Inhibitor (C1 INH) is part of a complex cascade of reactions that control the release of fluids from capillaries into the surrounding tissues, thereby causing oedema (swelling).

Hereditary Angioedema (HAE) is a rare condition; incidence 1/10,000 to 1/50,000 of the population. The condition has been recognised for well over 100 years, but until the 1990s the standard of treatment was very poor. Because HAE is such a rare condition most doctors would not see a case in their entire career and misdiagnosis was common. Inappropriate treatments, unnecessary operations and psychiatric referrals were not uncommon, and historically medical papers quoted that up to a third of patients died of laryngeal oedema. Even today many patients suffer for decades before they receive the correct diagnosis.

Types of Hereditary Angioedema

Type I and Type II HAE are due to a genetic mutation and there is a 50% chance that children will inherit the condition from an affected parent but unaffected parents cannot pass on HAE.

Type I

There are low levels of C1 INH (in most cases)

Type II

The blood levels are normal but the C1 INH has impaired function

Type III

This is a very rare recently documented form: It mainly affects females and is exacerbated by high oestrogen levels e.g. oral contraceptives and pregnancy. HAE type III is not due to C1 INH deficiency; it is linked to an increase in kininogenase activity leading to elevated levels of bradykinin.

Hereditary Angioedema
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