Methemoglobinemia epidemiology and demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief:
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Overview
Congenital (Hereditary) Methemoglobinemia
There are three main congenital conditions that lead to methemoglobinemia:
1. Cytochrome b5 reductase deficiency and pyruvate kinase deficiency
2. G6PD deficiency
3. Presence of abnormal hemoglobin (Hb M)
Acquired or Acute Methemoglobinemia
Most common cause include different oxidant drugs, toxins or chemicals
Epidemiology and Demographics
Epidemiology
In the United States congenital methemoglobinemia is rare. Deficiency of cytochrome b5 reductase endemic only in some Native American tribes like Navajo and Athabaskan Alaskans, and the Yakutsk people in Siberia.
The acquired methemoglobinemia is the most common form, and most cases are related to topical or local anesthetic use during medical procedures.
Demographics
Infants, particularly those younger than 4 months are most susceptible to methemoglobinemia. This is due to the fact that the NADH methemoglobin reductase activity and concentration (the main protective enzyme against oxidative stress) is not fully mature in infants. Both cytochrome b5 reductase deficiency and pyruvate kinase deficiency are autosomal recessive diseases and the Hb M has autosomal dominant pattern of inheritance. On the other hand G6PD deficiency is X-linked, therefore the risk of acquired methemoglobinemia is greater in males. The highest prevalence of G6PD deficiency is observed in the malaria-endemic regions: Sub-Saharan Afria, West Asia and Arabian Peninsula, as well as in people of Mediterranean descent. As a result these populations are at higher risk for acquired methemoglobinemia.