Esophageal atresia with right pulmonary agenesis.

parents and sibling Fourthly, there was no family history suggestive of methemoglobinemia and methemoglobrn levels of both the parents and elder sibling were normal Fifthly, There is transient physiologic deficiency of cytochrome b5 reductive activity in neonates approximately 60% of the normal adult value, and even greater reduction in premature neonates is known making them more susceptible to oxidant stress leading to methemoglobinemia(3,4) Sixthly, if we consider the possibility of neonate having homozygous cytochrome b5 reductase deficiency and both parents heterozygotes having normal levels of methemoglobrn, the mother, if she was heterozygote could have manifested with methemoglobinemia to strong oxident stress of Dapsone therapy(3) Finally though we were unable to estimate cytochrome b5 reductase enzymatic activity, the prompt response to smgle dose of methylene blue and non recurrence of methemoglobinemia in five months of follow up in the patient subsequently, probably excludes enzymes deficiency as a cause of methemaglobinemia(3)