Decoding Pseudocholinesterase Deficiency: Understanding, Diagnosing, and the Role of Genetic Testing

Expert Reviewed By: ⁠Dr. Brandon Colby MD

Pseudocholinesterase deficiency is a rare genetic disorder that affects the body’s ability to break down certain drugs, such as muscle relaxants used during anesthesia. This can lead to prolonged neuromuscular block and other complications. Understanding, diagnosing, and managing this condition is essential for healthcare providers, especially in the context of surgical procedures. This article delves into the complexities of pseudocholinesterase deficiency, the importance of genetic testing, and the latest research on the subject.

Understanding Pseudocholinesterase Deficiency

Pseudocholinesterase, also known as serum cholinesterase or butyrylcholinesterase, is an enzyme produced by the liver that plays a crucial role in breaking down certain drugs, including muscle relaxants like mivacurium and succinylcholine. Pseudocholinesterase deficiency is a genetic condition that leads to reduced enzyme activity, making it difficult for the body to metabolize these drugs. This can result in prolonged neuromuscular block, which may manifest as muscle weakness, difficulty breathing, or even paralysis after receiving anesthesia.

There are two main types of pseudocholinesterase deficiency: a heterozygous form, where a person has one abnormal gene and one normal gene, and a homozygous form, where a person has two abnormal genes. The heterozygous form is more common and typically results in a milder deficiency, while the homozygous form is rarer and can lead to a more severe deficiency.

Diagnosing Pseudocholinesterase Deficiency

Diagnosing pseudocholinesterase deficiency can be challenging due to the variability in enzyme concentrations among individuals and the lack of standardized testing methods. However, measuring serum cholinesterase activity is a common approach to assess liver function and detect enzyme deficiencies1.

In some cases, the deficiency may only be discovered after a patient experiences a prolonged neuromuscular block following the administration of anesthesia. For example, a case report describes a 75-year-old woman who experienced a 10-hour neuromuscular block after receiving mivacurium due to a major pseudocholinesterase deficiency2.

Managing Pseudocholinesterase Deficiency in the Post-operative Patient

For patients with known or suspected pseudocholinesterase deficiency, it is crucial to carefully manage their post-operative care. This may include maintaining intubated status until the patient’s ability to draw proper tidal volumes returns4. Additionally, healthcare providers should be aware of alternative anesthetic agents that can be used in patients with this condition.

The Role of Genetic Testing in Pseudocholinesterase Deficiency

Identifying Genetic Causes

Genetic testing can help identify the specific gene mutations responsible for pseudocholinesterase deficiency. This can be particularly useful for individuals with a family history of the condition or those who have experienced prolonged neuromuscular block after anesthesia. Knowing the genetic cause can help healthcare providers make informed decisions about anesthesia management and post-operative care.

Animal Models for Understanding the Disease’s Pathobiology

Genetic testing has also played a significant role in the development of animal models for studying pseudocholinesterase deficiency. By identifying and characterizing the genes associated with the condition, researchers can create mouse models that mimic the human disease. These models can help researchers better understand the pathobiology of pseudocholinesterase deficiency and potentially develop new treatment strategies3.

Screening and Counseling

Genetic testing can also be used for screening purposes, particularly in populations with a higher prevalence of pseudocholinesterase deficiency. This can help identify individuals at risk for the condition and provide them with appropriate counseling and guidance on anesthesia management and potential complications.

In conclusion, understanding, diagnosing, and managing pseudocholinesterase deficiency is essential for healthcare providers to ensure the safety and well-being of their patients. Genetic testing plays a crucial role in identifying the genetic causes of the condition, developing animal models for research, and screening and counseling at-risk individuals. As our knowledge of this rare disorder continues to grow, so too will our ability to effectively diagnose and manage it.

About The Expert Reviewer

Dr. Brandon Colby MD is a US physician specializing in the personalized prevention of disease through the use of genomic technologies. He’s an expert in genetic testing, genetic analysis, and precision medicine. Dr. Colby is also the Founder of  and the author of ⁠⁠Outsmart Your Genes.

Dr. Colby holds an MD from the Mount Sinai School of Medicine, an MBA from Stanford University’s Graduate School of Business, and a degree in Genetics with Honors from the University of Michigan. He is an Affiliate Specialist of the American College of Medical Genetics and Genomics (⁠⁠ACMG), an Associate of the American College of Preventive Medicine (⁠⁠ACPM), and a member of the National Society of Genetic Counselors (⁠NSGC)