Linkage studies inhereditary angio-oedema

Hereditary angio-oedema (HAE)isafamilial disease characterised byrecurrent attacks ofangio-oedema inthesubcutaneous tissues, andsometimes inthe bowelandintherespiratory tract. Attacks inthe respiratory tract mayproduce fatal asphyxia. The disease isinherited asanautosomal dominant trait andiscaused bydeficiency ofCT-inhibitor (aneuraminoglycoprotein). Thepatients areheterozygousforthegenedetermining HAE andhave generally intheregion ofone-sixth ofthenormal level ofCl-inhibitor intheir serum. Inthemajority (about 85%)ofpedigrees thefunctional inhibitor deficiency isparalleled bydeficiency oftheprotein measured antigenically. Inabout15% ofpedigrees a dysfunctional protein canbefoundbyantigenic measurement.