Objective: To investigate genetic mutations in three Japanese subjects homozygous for silent butyrylcholinesterase mutations.
Methods and results: One of them was compound heterozygous for two mutations; GGA(Gly) to CGA(Arg) at codon 365 (G365R) and CAA(Gln) to TAA(Ter) at codon 119 (Q119X). The other two subjects were homozygous for different missense mutations: CGT(Arg) to TGT(Cys) at codon 515 (R515C) and G365R, respectively. Simple identification methods for all of the mutations were developed and applied for family analysis and to control individuals. Two mutations, G365R and R515C, have been reported in the Japanese population, while the nonsense mutation Q119X was discovered in the present study. Genetic heterogeneity between human populations with regard to the butyrylcholinesterase gene was suggested.
Conclusions: Among the three mutations found in this investigation, one was novel, and none of these mutations have been reported outside Japan.