Several genetic variants of human butyrylcholinesterase (EC 3.1.1.8; serum cholinesterase; pseudocholinesterase; BCHE) are reportedly associated with prolonged apnoea in patients given the muscle relaxant drug succinylcholine (Scoline). An estimation of the serum BCHE activity, dibucaine number (DN) and fluoride number (FN) have, in the past, been sufficient to identify most of the known BCHE phenotypes associated with succinylcholine sensitivity. However, several additional BCHE variants have been discovered in the last 10 – 20 years, which complicates the phenotyping of individuals. It has, therefore, become necessary to distinguish between butyrylcholinesterase at the DNA level (BCHE) and at the protein level (BChE). The genotype of an individual represents the actual point mutations (or lack of them) present in the DNA of the BCHE gene, whilst the phenotype reflects properties of the BChE protein itself.
The phenotype does not always accurately reflect the genotype. For example, inhibition tests are unable to discriminate between quantitative variants and the usual (wild-type or normal) enzyme except when in the presence of the heterozygous atypical (Dibucaine-resistant) variant.
Cholinesterase phenotyping has thus been replaced by a plasma activity as well as genotyping.
Lipids/Trace Metals
CHE
Send whole blood for all request for phenotyping to Specialist Chemistry not Genetics
Dibucaine Number
Fluoride Number
Phenotype for cholinesterase
3 weeks
3450