Molecular genetic survey of five Japanese families with high-molecular-weight kininogen deficiency

Analyses of the kininogen (KGN) molecule and KGN gene status in five Japanese families with high-molecular-weight (HMW) KGN deficiency were performed by the immunoblotting method with monoclonal antibodies to HMW-KGN, and by the Southern blotting method with the cDNA for human low-molecular-weight prekininogen. No molecular abnormality of KGN was detected in the DNA from four patients with total KGN deficiency or one patient with isolated HMW-KGN deficiency. In the former, the KGN gene appeared to be grossly normal at the level of the whole genome on Southern blotting. In isolated HMW-KGN deficiency, a partial deletion in intron 7 was found by restriction analyses of EcoRI, BamHI, HindIII, Sca I, and Bgl II fragments. This partial deletion is assumed to be related to an abnormality of the alternative RNA splicing events for HMW-prekininogen mRNA.