A family with hereditary serum cholinesterase deficiency

Analysis of mutation of the plasma cholinesterase gene in a man who had died following a traffic accident

We analyzed mutation of the butyrylcholinesterase (BCHE) gene in a 69-year-old man on whom a forensic autopsy had been performed after he had died following a traffic accident. Extremely low plasma cholinesterase activity had been pointed out by the emergency doctor at the hospital prior to his death and based on this, organophosphorus poisoning had been suspected. However, no pesticides, which could have reduced the plasma cholinesterase activity, were detected by toxicological analysis using GC/MS. Subsequently, one base insertion was found in exon 2. The frame shift mutation had occurred because a homozygous extra T had been inserted between nucleotides 1343 and 1344, resulting in the appearance of a stop codon in codon 454 (AGA454TAA, Arg454stop). This heterozygous frame shift mutation at this point was identified in the man's son. It is likely that there may be many such latent patients with abnormal plasma cholinesterase activity, and accordingly we should always bear this fact in mind and should carry out molecular genetic testing for an accurate diagnosis of this deficiency.

Genetic mutations of butyrylcholine esterase identified from phenotypic abnormalities in Japan

We have identified 12 kinds of genetic mutations of butyrylcholine esterase (BCHE) from phenotypic abnormalities, showing that BCHE activities were deficient or diminished in sera. These genetic mutations, detected by PCR–single-strand conformation polymorphism analysis and direct sequencing, consisted of one deletion (BCHE*FS4), nine missense (BCHE*24 M, *100S, *250P, *267R, *330I, *365R, *418S, *515C, *539T), and two nonsense mutations (BCHE*119STOP, *465STOP). All of the individuals deficient in serum BCHE activity were homozygous for silent genes (6 of 6). Fifty-eight percent of the individuals (31 of 53) with slightly reduced serum BCHE activity were heterozygous for silent genes. They also showed a higher frequency (47% as allele frequency) of the K-variant than the general population (17.5%). Finally, we confirmed low serum BCHE activity in 10 of 23 individuals heterozygous for silent genes.