Myeloperoxidase (MPO) deficiency is primarily caused by mutations in the MPO gene on chromosome 17q22-23, a genetic condition inherited in an autosomal recessive pattern. A less common form can also arise from somatic mutations of the same gene.
Understanding the Causes of MPO Deficiency
Myeloperoxidase (MPO) deficiency, a condition first identified in 1954, can manifest in two main forms, each with a distinct underlying cause:
1. Hereditary MPO Deficiency (Primary Cause)
This is the most common form of MPO deficiency and is a direct result of inherited genetic factors.
- Genetic Basis: It is caused by specific mutations within the MPO gene.
- Gene Location: The MPO gene is situated on chromosome 17, specifically within the 17q22-23 region. This location is critical as it dictates where the genetic instructions for producing MPO are found.
- Inheritance Pattern: This form is characterized by autosomal recessive inheritance. This means an individual must inherit two copies of the mutated MPO gene—one from each parent—to develop the condition. If only one mutated copy is inherited, the individual is typically a carrier and does not show symptoms.
2. Secondary MPO Deficiency
Less frequent than the hereditary form, secondary MPO deficiency results from mutations that are not inherited.
- Somatic Mutations: This type arises from somatic mutations of the MPO gene. Unlike hereditary mutations, somatic mutations occur after conception and are present in only certain cells, not throughout the entire body. They are not passed down from parents to children.
- Acquired Nature: These mutations are acquired during a person's lifetime and can be associated with other medical conditions or exposures, rather than being present from birth due to parental inheritance.
Summary of MPO Deficiency Causes
The following table provides a clear distinction between the two forms of MPO deficiency based on their underlying causes:
| Type of MPO Deficiency | Primary Cause | Inheritance Pattern | Frequency |
|---|---|---|---|
| Hereditary | Mutations in the MPO gene on chromosome 17q22-23 | Autosomal recessive | More frequent |
| Secondary | Somatic mutations of the MPO gene | Not inherited (acquired) | Less frequent |
Understanding these distinct causes is crucial for accurate diagnosis and management of MPO deficiency.
