As a hematologist with extensive experience in the study of blood disorders, I can provide you with an informed perspective on methemoglobinemia. Methemoglobinemia is a condition characterized by the presence of an abnormally high level of methemoglobin in the blood. Methemoglobin is a form of hemoglobin that cannot effectively bind oxygen. There are two main types of methemoglobinemia: congenital and acquired.

Congenital methemoglobinemia is indeed genetic. It is caused by mutations in genes responsible for the production of enzymes that are involved in the normal regulation of hemoglobin. Specifically, mutations in the genes for cytochrome b5 reductase or NADH methemoglobin reductase can lead to this condition. These mutations are inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene (one from each parent) to express the disease.

Acquired methemoglobinemia, on the other hand, is not genetic. It can result from exposure to certain chemicals or medications that oxidize the iron in hemoglobin to a form that cannot bind oxygen. Common culprits include nitrates found in well water or certain foods, as well as medications like certain local anesthetics and antimalarial drugs.

In summary, while congenital methemoglobinemia has a genetic basis, acquired methemoglobinemia does not and is instead caused by environmental factors.

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Autosomal recessive congenital methemoglobinemia is caused by mutations in the CYB5R3 gene. This gene provides instruction for making an enzyme called cytochrome b5 reductase 3. This enzyme is involved in transferring negatively charged particles called electrons from one molecule to another.read more >>