A familial study of C5+cholinesterase and its frequency in the normal population.

A case of familial hypercholinesterasemia was presented. A cholinesterase isoenzyme study revealed the extra C5 band nearer to the cathode than C4 on the gradient polyacrylamide gel electrophoresis in 6 out of 8 subjects in the family. No significant difference in the effect of inhibitors and activator was found when compared with the normal control. We investigated the frequency of variant with C5+cholinesterase in normal healthy subjects. The frequency of the extra C5 band found in the normal healthy population in Japan was 1.2%. It was considered to be clinically useful for differential diagnosis of patients with elevated serum cholinesterase to find subjects with familial hypercholinesterasemia.