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.
There are low levels of C1 INH (in most cases)
The blood levels are normal but the C1 INH has impaired function
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.