Pseudocholinesterase deficiency is a condition in which a person's body is abnormally slow at breaking down a certain class of drugs used for surgical anesthesia. Known as choline esters, the most commonly used of these drugs is called succinylcholine (suxamethonium). This drug is used by doctors to induce muscle relaxation and temporary paralysis, often for the purpose of inserting a breathing tube. After receiving a normal dose of succinylcholine, people with pseudocholinesterase deficiency will experience a longer than normal period of breathing paralysis. Typically medical teams who administer these drugs would be equipped to handle such an event.
People who are carriers of pseudocholinesterase deficiency - that is, people who have one copy of the gene with a mutation and one normal copy - show a slightly prolonged period of breathing paralysis after receiving choline ester drugs. This period lasts longer than 5 minutes but less than an hour. For people with two mutated copies of the gene, this episode lasts more than an hour and can last as long as three hours.
Less than 1 in 1000 people have pseudocholinesterase deficiency. It is more common among the some Alaskan Eskimos, where it may affect as many as 10%. In the Persian Jewish community, 1 in 10 individuals is a carrier of the mutation screened by Counsyl. Among white Americans, the mutation screened by Counsyl is thought to affect 1 in 3,000.
No treatment is required on a day to day basis. If a person with pseudocholinesterase deficiency does receive choline ester drugs and does not resume independent breathing at the expected time, mechanical ventilation can help him or her do so until the body naturally begins breathing on its own.
The prognosis is very good. Unless an affected person is given choline ester drugs, pseudocholinesterase deficiency does not produce any symptoms.
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