Butyrylcholinesterase deficiency

Butyrylcholinesterase deficiency is a rare genetic condition characterized by the decreased activity or absence of the butyrylcholinesterase (BChE) enzyme in the body. Butyrylcholinesterase, also known as pseudocholinesterase or plasma cholinesterase, plays a crucial role in the hydrolysis of ester-based drugs, including certain types of anesthetics and muscle relaxants such as succinylcholine and mivacurium. The deficiency can lead to prolonged paralysis and apnea following the administration of these drugs during surgical procedures, posing significant risks to affected individuals.

Causes

Butyrylcholinesterase deficiency is primarily caused by genetic mutations in the BCHE gene, which provides instructions for producing the butyrylcholinesterase enzyme. These mutations can lead to the production of an enzyme with reduced activity or the complete absence of enzyme activity. The condition is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to be affected.

Symptoms

The primary symptom of butyrylcholinesterase deficiency is an increased sensitivity to certain muscle relaxants used in anesthesia, leading to prolonged muscle relaxation and respiratory depression after surgery. This can result in a longer recovery time from anesthesia and, in severe cases, may require extended mechanical ventilation. Individuals with this condition may not exhibit any symptoms until they are exposed to the triggering drugs.

Diagnosis

Diagnosis of butyrylcholinesterase deficiency typically involves a combination of clinical evaluation and laboratory testing. The Dibucaine Number test and the fluoride number test are commonly used to assess the enzyme's activity in the plasma. Genetic testing can also be performed to identify mutations in the BCHE gene.

Treatment

There is no specific treatment for butyrylcholinesterase deficiency. Management of the condition primarily involves avoiding the use of certain anesthetics and muscle relaxants known to cause prolonged effects in affected individuals. Alternative drugs with a lower risk of prolonged paralysis should be used when possible. In emergency situations where these drugs must be used, patients may require extended postoperative respiratory support.

Prevention

Preventive measures include genetic counseling for individuals with a family history of butyrylcholinesterase deficiency. This can help potential carriers understand their risks of passing the condition onto their children. Preoperative screening for butyrylcholinesterase activity may also be recommended for patients with a personal or family history suggestive of the condition.