In one family of twenty-four members hereditary angio-oedema was present in the family for six generations. The protein C1 esterase inactivator found in nine patients proved to be non-active in a functional test. Another anomaly found in the complementary system was labelled C3 nephritic factor without any renal, or other clinical symptoms.
Study of HL-A haplotypes did not show any linkage with the loci A, B and C.
Hereditary angio-oedema is a disease arising from a specific defect in the inactivator of the C1 esterase (CĪ INA) which is a regulating component of the complement system (Donaldson & Evans, 1963). This system is of current interest because of its interaction with other mechanisms of inflammation. Moreover, some links have been discovered recently between HL-A and hereditary defects of complement.
This paper reports new findings in a family with hereditary angio-oedema