Frequency and enzyme activity of the butyrylcholinesterase K-variant in a Turkish population

Objective. Among variants of the butyrylcholinesterase gene (BChE), the K-variant causing Ala539Thr substitution is the most common one associated with about one-third reduction in the enzyme activity. This study aimed to detect the frequency of the K-variant allele in a Turkish population sample and also to evaluate how the plasma BChE activity was influenced by this variant. Methods. Patients administered for elective surgery (n=77) were examined for the presence of the K allele. The enzyme activity was determined in plasma. Results. The K-variant of BChE is a common allele with a frequency of 0.266 (CI95% 0.196-0.336) in our sample from a Turkish population. Mean enzyme activity in subjects homozygous for the K-variant was about 40% lower than other subjects. Conclusion. The frequency of the BChE K-variant was significantly higher in a Turkish population than those reported for other populations and it is associated with a diminished enzyme activity.