Methaemoglobinaemia arises from the production of non-functional haemoglobin containing
oxidised Fe3+ which results in reduced oxygen supply to the tissues and manifests as
cyanosis in the patient. It can develop by three distinct mechanisms: genetic mutation
resulting in the presence of abnormal haemoglobin, a deficiency of methaemoglobin
reductase enzyme and toxin-induced oxidation of haemoglobin. The normal haemoglobin
fold forms a pocket to bind the haem and stabilise its complex with molecular oxygen …