A PCR based method to determine the Kalow allele of the cholinesterase gene: the E1k allele frequency and its significance in the normal population.

The Kalow allele for cholinesterase is a quantitative variant of the usual gene and has been shown to result from a single base pair change in the DNA. A new method based on the polymerase chain reaction to distinguish Kalow alleles of the cholinesterase gene was developed. Using the amplification refractory mutagenesis system, two different reactions distinguished the presence of a guanine (normal E1u allele) from that of an adenine (Kalow E1k allele) at nucleotide 1615 within the coding sequences of the gene. The frequency of the Kalow allele in our sample of 51 persons was determined to be 20%. The mean total cholinesterase activity in heterozygotes was 90% of that in persons who typed as E1uE1u homozygotes. Two E1kE1k homozygotes were identified and their cholinesterase activities were the two lowest measured.