Methemoglobinemia Due to Deficiency of Methemoglobin Reductase, also known as methemoglobinemia, type i, is related to methemoglobinemia and ambiguous genitalia and pyruvate dehydrogenase e3-binding protein deficiency, and has symptoms including ataxia, cyanosis and headache. An important gene associated with Methemoglobinemia Due to Deficiency of Methemoglobin Reductase is CYB5R3 (Cytochrome B5 Reductase 3). The drugs Methylene blue and Enzyme Inhibitors have been mentioned in the context of this disorder. Affiliated tissues include skin and brain, and related phenotypes are intellectual disability and global developmental delay