Table 1.

Classification of hereditary angioedema.

TYPE	DEFECT
Type I – Quantitative	Decreased C1 inhibitor synthesis
Type II - Functional; Qualitative	Decreased C1 inhibitor function
Type III	Normal C1 inhibitor levels and function
	A- Estrogen-dependent or estrogen-related
	B- Mutation of factor XII (Hageman factor)
	C- Idiopathic