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Genetic and Rare Diseases Information Center (GARD)

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Pseudocholinesterase deficiency

Other Names for this Disease
  • Apnea, Postanesthetic
  • Butyrylcholinesterase deficiency
  • Cholinesterase 2 Deficiency
  • Pseudocholinesterase E1
  • Succinylcholine Sensitivity
More Names
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Your Question

I was told that I had pseudocholinesterase deficiency after I experienced difficulty in the resumption of breathing following surgery with general anesthesia. Is there a test that can verify this diagnosis? Are my children at risk for this condition?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is pseudocholinesterase?

Pseudocholinesterase (also known as butyrylcholinesterase or plasma cholinesterase) is an enzyme which breaks down acetylcholine, a chemical critical in the transmission of nerve impulses.  Pseudocholinesterase is made primarily in the liver and circulates in the blood.[1] 
Last updated: 10/23/2013

What is pseudocholinesterase deficiency?

Pseudocholinesterase deficiency is a condition that causes increased sensitivity to certain muscle relaxant drugs used during general anesthesia, called choline esters. These drugs relax the muscles used for movement, including the muscles needed for breathing. They are normally broken down by the body within a few minutes of being given, 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, therefore needing mechanical ventilation until the drugs are cleared from the body. Affected individuals may also have increased sensitivity to certain other drugs and to specific agricultural pesticides. Pseudocholinesterase deficiency can be inherited in an autosomal recessive manner and caused by mutations in the BCHE gene, or it can have non-genetic causes in which case it is called acquired pseudocholinesterase deficiency.[2]
Last updated: 10/16/2013

What causes of pseudocholinesterase deficiency?

There are inherited and acquired causes of the pseudocholinesterase deficiency.[3]

The inherited form of the condition is caused by mutations (changes) in the genes that produce pseudocholinesterase.  The mutations cause the gene to produce inadequate amounts of pseudocholinesterase or to produce abnormal forms of the enzyme.  Individuals that have only one mutated pseudocholinesterase gene have partial deficiency in enzyme activity, which results in a slightly prolonged duration of paralysis, longer than 5 minutes but shorter than 1 hour, following the administration of succinylcholine.  Less than 0.1% of the general population carries two mutated copies of the pseudocholinesterase gene that will produce clinically significant effects from succinylcholine lasting longer than 1 hour.[3] 

The acquired causes of pseudocholinesterase deficiency include the following:  chronic infections, extensive burn injuries, liver disease, cancer, malnutrition, and taking certain medications.[3]

Last updated: 3/3/2010

How is pseudocholinesterase deficiency diagnosed?

Although the diagnosis is suspected after an episode of prolonged respiratory paralysis following administration of succinylcholine, the diagnosis of pseudocholinesterase deficiency is confirmed by a laboratory test.[3] Serum cholinesterase is a test for the enzymes acetylcholinesterase (also known as RBC cholinesterase) and pseudocholinesterase (also known as butyrylcholinesterase or plasma cholinesterase), which act to break down acetylcholine, a chemical critical in the transmission of nerve impulses.  This test may be performed prior to anesthesia with succinylcholine (a paralyzing agent that is eliminated by these enzymes) to exclude a genetic deficiency of these enzymes. This is often done in individuals who have a family history of a prolonged drug effect during anesthesia.[1]
Last updated: 4/12/2013

How is pseudocholinesterase deficiency inherited?

Pseudocholinesterase deficiency is inherited in an autosomal recessive manner.[4] Individuals who inherit one copy of the  mutated pseudocholinesterase gene have partial deficiency in enzyme activity, which results in a slightly prolonged duration of paralysis, longer than 5 minutes but shorter than 1 hour, following the administration of succinylcholine. A very small percentage of the population inherits two copies of the mutated gene. These individuals have symptoms that may last 1 hour or longer.[3]

Individuals who wish to learn more about their risk of inheriting or passing on the gene for pseudocholinesterase deficiency should seek the advice of a genetics professional. Visit the Services section to learn how you can find a genetics professional in your area.
Last updated: 3/3/2010

What treatment is available for pseudocholinesterase deficiency?

Individuals with pseudocholinesterase deficiency should avoid exposure to exogenous (outside of the body) sources of choline esters. The mainstay of treatment for patients in the midst of prolonged paralysis is mechanical ventilatory support until respiratory muscle paralysis spontaneously resolves. Recovery eventually occurs as a result of passive diffusion of succinylcholine away from the neuromuscular junction.[3]
Last updated: 3/3/2010

How can I avoid exogenous sources of choline esters that might trigger a reaction?

Individuals with known pseudocholinesterase deficiency may wear a medic-alert bracelet that will notify healthcare workers of increased risk from administration of succinylcholine. Affected individuals may be at increased risk of toxic reactions, including sudden cardiac death, associated with recreational use of cocaine.[5]
Last updated: 10/23/2013

Where can I obtain a medic-alert bracelet?

You can contact the MedicAlert Foundation using the contact information below.  The MedicAlert Foundation is a non-profit healthcare organization that is dedicated to providing services to protect and save lives.

MedicAlert Foundation International
2323 Colorado Avenue
Turlock, CA 95382
Toll free:  888-633-4298
Telephone:  209-668-3333
Fax: 209-669-2450
Online E-mail form:
Web site:

Last updated: 10/16/2013