Myeloperoxidase deficiency

Myeloperoxidase deficiency is a disorder in which there is too little myeloperoxidase, or too little working myeloperoxidase, an iron-containing protein found mainly in the granules of neutrophils. It comes in two forms: a primary inherited form and a secondary acquired form. Without working myeloperoxidase the neutrophils kill intracellular pathogens less efficiently, particularly Candida albicans, and release fewer neutrophil extracellular traps. Even so, more than 95 percent of affected people have no symptoms in their lifetime, and when symptoms occur the most common is repeated infection with Candida albicans, especially in people who also have diabetes mellitus. Affected people also show higher rates of chronic inflammatory conditions. The primary form is an autosomal recessive genetic disorder caused by mutations in the myeloperoxidase gene on chromosome 17q23. The secondary form occurs in situations such as blood cancers, some drugs, iron deficiency, lead intoxication, pregnancy and severe infection, and it usually resolves when the underlying cause is treated. The condition is diagnosed with flow cytometry or cytochemical stains. There is no treatment for the deficiency itself, and any infections that occur are treated as they arise. Reported frequency is about 1 in 1,000 to 1 in 4,000 people in the United States and Europe and about 1 in 55,000 in Japan. This entry records what the source states and is not medical advice.