Pseudocholinesterase deficiency is a condition that results in increased sensitivity to certain muscle relaxant drugs used during general anesthesia, called choline esters. These fast-acting drugs, such as succinylcholine and mivacurium, are given to relax the muscles used for movement (skeletal muscles), including the muscles involved in breathing. The drugs are often employed for brief surgical procedures or in emergencies when a breathing tube must be inserted quickly. Normally, these drugs are broken down (metabolized) by the body within a few minutes of being administered, at which time the muscles can move again. However, people with pseudocholinesterase deficiency may not be able to move or breathe on their own for a few hours after the drugs are administered. Affected individuals must be supported with a machine to help them breathe (mechanical ventilation) until the drugs are cleared from the body.

People with pseudocholinesterase deficiency may also have increased sensitivity to certain other drugs, including the local anesthetic procaine, and to specific agricultural pesticides. The condition causes no other signs or symptoms and is usually not discovered until an abnormal drug reaction occurs.

Pseudocholinesterase deficiency occurs in 1 in 3,200 to 1 in 5,000 people. It is more common in certain populations, such as the Persian Jewish community and Alaska Natives.

Pseudocholinesterase deficiency can be caused by mutations in the BCHE gene. This gene provides instructions for making the pseudocholinesterase enzyme, also known as butyrylcholinesterase, which is produced by the liver and circulates in the blood. The pseudocholinesterase enzyme is involved in the breakdown of choline ester drugs. It is likely that the enzyme has other functions in the body, but these functions are not well understood. Studies suggest that the enzyme may be involved in the transmission of nerve signals.

Some BCHE gene mutations that cause pseudocholinesterase deficiency result in an abnormal pseudocholinesterase enzyme that does not function properly. Other mutations prevent the production of the pseudocholinesterase enzyme. A lack of functional pseudocholinesterase enzyme impairs the body's ability to break down choline ester drugs efficiently, leading to abnormally prolonged drug effects.

Pseudocholinesterase deficiency can also have nongenetic causes. In these cases, the condition is called acquired pseudocholinesterase deficiency; it is not inherited and cannot be passed to the next generation. Activity of the pseudocholinesterase enzyme can be impaired by kidney or liver disease, malnutrition, major burns, cancer, or certain drugs.

Genetic Testing Information

• Genetic Testing Registry: Deficiency of butyrylcholinesterase

Genetic and Rare Diseases Information Center

• Butyrylcholinesterase deficiency

Patient Support and Advocacy Resources

• National Organization for Rare Disorders (NORD)

Clinical Trials

• ClinicalTrials.gov

Catalog of Genes and Diseases from OMIM

• BUTYRYLCHOLINESTERASE; BCHE

Scientific Articles on PubMed

• PubMed

• Garcia DF, Oliveira TG, Molfetta GA, Garcia LV, Ferreira CA, Marques AA, Silva WA Jr. Biochemical and genetic analysis of butyrylcholinesterase (BChE) in a family, due to prolonged neuromuscular blockade after the use of succinylcholine. Genet Mol Biol. 2011 Jan;34(1):40-4. doi: 10.1590/S1415-47572011000100008. Epub 2011 Mar 1. Citation on PubMed or Free article on PubMed Central
• Gatke MR, Bundgaard JR, Viby-Mogensen J. Two novel mutations in the BCHE gene in patients with prolonged duration of action of mivacurium or succinylcholine during anaesthesia. Pharmacogenet Genomics. 2007 Nov;17(11):995-9. doi: 10.1097/FPC.0b013e3282f06646. Citation on PubMed
• Leadingham CL. A case of pseudocholinesterase deficiency in the PACU. J Perianesth Nurs. 2007 Aug;22(4):265-71; quiz 272-4. doi: 10.1016/j.jopan.2007.05.005. Citation on PubMed
• Levano S, Ginz H, Siegemund M, Filipovic M, Voronkov E, Urwyler A, Girard T. Genotyping the butyrylcholinesterase in patients with prolonged neuromuscular block after succinylcholine. Anesthesiology. 2005 Mar;102(3):531-5. doi: 10.1097/00000542-200503000-00009. Citation on PubMed
• Maiorana A, Roach RB Jr. Heterozygous pseudocholinesterase deficiency: a case report and review of the literature. J Oral Maxillofac Surg. 2003 Jul;61(7):845-7. doi: 10.1016/s0278-2391(03)00163-0. No abstract available. Citation on PubMed
• Soliday FK, Conley YP, Henker R. Pseudocholinesterase deficiency: a comprehensive review of genetic, acquired, and drug influences. AANA J. 2010 Aug;78(4):313-20. Citation on PubMed
• Yen T, Nightingale BN, Burns JC, Sullivan DR, Stewart PM. Butyrylcholinesterase (BCHE) genotyping for post-succinylcholine apnea in an Australian population. Clin Chem. 2003 Aug;49(8):1297-308. doi: 10.1373/49.8.1297. Citation on PubMed
• Zelinski T, Coghlan G, Mauthe J, Triggs-Raine B. Molecular basis of succinylcholine sensitivity in a prairie Hutterite kindred and genetic characterization of the region containing the BCHE gene. Mol Genet Metab. 2007 Feb;90(2):210-6. doi: 10.1016/j.ymgme.2006.10.009. Epub 2006 Dec 12. Citation on PubMed
• Zencirci B. Pseudocholinesterase enzyme deficiency: a case series and review of the literature. Cases J. 2009 Dec 4;2:9148. doi: 10.1186/1757-1626-2-9148. Citation on PubMed or Free article on PubMed Central