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Ency. home > Disease > M > Methemoglobinemia

Methemoglobinemia   

Overview | Symptoms | Treatment | Prevention

Definition:

A condition in which the iron in the hemoglobin molecule (the red blood pigment) is defective, making it unable to carry oxygen effectively to the tissues.

Causes and Risks

There are two forms of inheritable methemoglobinemia. Most hereditary cases result from a deficiency in the enzyme cytochrome b5 reductase (Type II).  

The other inheritable type, called hemoglobin M disease (Type I), is an autosomal dominant condition (which means you only need one affected parent to inherit it) characterized by an inability to convert methemoglobin back to hemoglobin.  This usually causes few problems.

Exposure to certain chemicals may also cause an increase in the production of methemoglobin. These chemicals include nitrites (used commonly to prevent spoilage of meat), xylocaine, and benzene.

Ency. home > Disease > M > Methemoglobinemia

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