Hemoglobin F-Toms River

[MIM 613 977]

Very rare. Congenital abnormality of the fetal hemoglobin where valine is replaced by methionine in position 67 in the  γ chain. All cases reported to date were de novo mutations of the HBG2 gene (11p15.4).


This anomaly results in:

-        decreased affinity of HbF for oxygen and therefore a cyanosis without hypoxemia that does not respond well to the administration of oxygen

-        moderate anemia.


Cyanosis and anemia improve progressively as the HbF γ chain is replaced by the adult Hb β chain. Healing is complete around 5-6 months of age.

Other neonatal hemoglobinopathies caused by a mutation in the HbF γ chain can lead to congenital methemoglobinemia (see congenital Methemoglobinemia).


These are:

-        HFM-Osaka: where histidine is replaced by tyrosine in position 63

-        HFM-Fort Ripley: where histidine is replaced by tyrosine in position 92

-        HFM-Circleville: where histidine is replaced by leucine in position 63

-        HFM-Cincinnatti: where phenylalanine is replaced by serine in position 41

-        HFM-Viseuo: where leucine is replaced by methionjine in position 28, altering the configuration of Hb in position 63


Anesthetic implications:

neonatal cyanosis without hypoxemia; transcutaneous paO2 monitoring


References :

-        Crawley MA, Mollan TL, Abdulmalik OY, Butler AD et al.
A hemoglobin variant associated with neonatal cyanosis and anemia.
NEJM 2011; 364(19): 1837-43.


Updated: December 2019