hereditary methemoglobinemia (Monarch Disease Ontology term MONDO_0018963) can be described as follows. Methemoglobinemia inherited in an autosomal recessive pattern. It is caused by deficiency of the enzyme NADH methemoglobin reductase or the presence of abnormal hemoglobin M. It presents with cyanosis early in life. There is no evidence of cardiopulmonary disease present. Also known as: autosomal recessive methemoglobinemia, congenital methemoglobinemia.