Frequencies of the Butyrylcholinesterase K Mutation in Southern Brazilian Population Samples of European and African Origin

The K mutation determines a variant butyrylcolinesterase (BChE) whose retarded synthesis or accelerated degradation leads to a 33% reduction of activity in comparison to the usual enzyme (1). The BCHE UK and BCHE K phenotypes are only identified by direct DNA analysis, since the quantitative effect of the K mutation cannot be detected by enzyme inhibition tests.