Pseudocholinesterase, deficiency ... (Pseudocholinesterase deficiency) - Gen BCHE.

Pseudocholinesterase deficiency is a condition that results in an increased sensitivity to certain muscle relaxants drugs used in general anesthesia, called choline esters. These fast acting medications such as succinylcholine and mivacurium are supplied to relax skeletal muscles, including the muscles involved in breathing. The drugs are often used for short surgical procedures or emergency when a tube must be inserted quickly breathing. Typically, these drugs are metabolized by the body within a few minutes of being administered, at which the muscles can move again. However, people with deficiency pseudocholinesterase may not be able to move or breathe on their own over a couple of hours after administering medications. Affected individuals require mechanical ventilation until the medication is eliminated from the body. People with pseudocholinesterase deficiency may also be more sensitive to other drugs, including procaine local anesthetic and specific agricultural pesticides.

This process is due to mutations in the BCHE gene, located on the long arm of chromosome 3 (3q26.1-q26.2). This gene encodes the enzyme pseudocholinesterase, also known as butyrylcholinesterase. This enzyme is encoded in the liver and circulates in the blood. Pseudocholinesterase enzyme is involved in the breakdown of choline ester drugs. It also helps protect the body decomposing certain toxic substances before they reach the nerves. These substances include certain pesticides, poisons that affect nerves and specific natural toxins that include a compound called solanine found in the skin of the green potato. The enzyme is likely to have other functions in the body, but these functions are not well understood. It is believed that the enzyme may be involved in the transmission of nerve signals.

There are more than 50 BChE gene mutations in people with deficient pseudocholinesterase. Some of these mutations replace pseudocholinesterase amino acids in the enzyme, resulting in an abnormal enzyme that is not working properly. Other mutations, prevent encoding the enzyme. Lack of functional pseudocholinesterase impairs the body's ability to efficiently decompose drugs choline ester, causing abnormally prolonged effects of drugs. Pseudocholinesterase deficiency may also have non - genetic causes. In these cases, the alteration is called pseudocholinesterase acquired deficiency, which is not inherited. Pseudocholinesterase activity enzyme can be affected by liver cancer or kidney disease, malnutrition, severe burns, or certain medications.

When the disease is due to genetic causes, it inherited with an autosomal recessive pattern, meaning that two copies of the gene in each cell have mutations. Very often, parents of a person with an autosomal recessive disorder have a copy of the altered gene in each cell and are called carriers. They can transmit the mutation of the gene to their children, but not often experience the signs and symptoms of the disease. In some cases, carriers of the BCHE gene mutations take longer than usual to remove choline ester of body drugs, but less time than individuals with two copies of the altered gene in each cell.

Tests in IVAMI: in IVAMI perform detection of mutations associated with pseudocholinesterase deficiency, by complete PCR amplification of the exons of the BCHE gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).