A case report of autosomal recessive methemoglobinemia in a child
4 affiliations
- 1Department of Emergency Medicine, American University of Beirut Medical Center, Beirut, Lebanon
- 2Department of Emergency Medicine, Khoula Hospital, Ministry of Health, Muscat, Oman
- 3Department of Emergency Medicine, Emory University, Atlanta, Georgia, USA
- 4Department of Pediatrics, Division of Pediatric Pulmonary and Critical Care, Faculty of Medicine, Vajira Hospital, Navamindradhiraj University, Bangkok, Thailand
Abstract
Methemoglobinemia is a rare hematologic disorder characterized by impaired oxygen delivery due to oxidation of hemoglobin iron from the ferrous (Fe2+) to the ferric (Fe3+) state, leading to elevated methemoglobin (MetHb) levels and cyanosis. We report the case of a 3-year-old female with a history of congenital cyanotic heart disease who presented with worsening cyanosis and was found to have a MetHb level of 49.3%. She responded initially to methylene blue therapy, but levels fluctuated over the following week. Whole-exome sequencing revealed a homozygous missense variant in the cytochrome b5 (CytB5) reductase 3 gene, consistent with autosomal recessive methemoglobinemia due to CytB5 reductase deficiency. The identified variant has not been previously reported and was classified as a variant of uncertain significance. This case underscores the importance of considering hereditary methemoglobinemia in children with unexplained cyanosis and persistent MetHb elevation. Genetic evaluation remains essential in suspected hereditary cases to inform prognosis, guide long-term care, and support family counseling.
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BibTeX
@article{khalil2026case,
title = {{A case report of autosomal recessive methemoglobinemia in a child}},
author = {Aline Khalil and Duaa AL Lawati and Patcha Yenjabog and Ziad Kazzi and Tharwat EL Zahran},
journal = {Turkish Journal of Emergency Medicine},
year = {2026},
month = oct,
doi = {10.4103/tjem.tjem_16_26},
url = {https://doi.org/10.4103/tjem.tjem_16_26},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - JOUR
TI - A case report of autosomal recessive methemoglobinemia in a child
AU - Aline Khalil
AU - Duaa AL Lawati
AU - Patcha Yenjabog
AU - Ziad Kazzi
AU - Tharwat EL Zahran
PY - 2026
DA - 2026/10/10
JO - Turkish Journal of Emergency Medicine
DO - 10.4103/tjem.tjem_16_26
UR - https://doi.org/10.4103/tjem.tjem_16_26
AB - Methemoglobinemia is a rare hematologic disorder characterized by impaired oxygen delivery due to oxidation of hemoglobin iron from the ferrous (Fe2+) to the ferric (Fe3+) state, leading to elevated methemoglobin (MetHb) levels and cyanosis. We report the case of a 3-year-old female with a history of congenital cyanotic heart disease who presented with worsening cyanosis and was found to have a MetHb level of 49.3%. She responded initially to methylene blue therapy, but levels fluctuated over the following week. Whole-exome sequencing revealed a homozygous missense variant in the cytochrome b5 (CytB5) reductase 3 gene, consistent with autosomal recessive methemoglobinemia due to CytB5 reductase deficiency. The identified variant has not been previously reported and was classified as a variant of uncertain significance. This case underscores the importance of considering hereditary methemoglobinemia in children with unexplained cyanosis and persistent MetHb elevation. Genetic evaluation remains essential in suspected hereditary cases to inform prognosis, guide long-term care, and support family counseling.
SN - 2452-2473
ER -