Extremely rare. Sporadic or autosomal dominant transmission of a mutation of the HBG2 gene (11p15.4). This causes a substitution of His by Tyr in position 63 on the HbF gamma chain : it reduces the affinity of HbF for O2 and transforms  it in methemoglobin. This causes neonatal cyanosis that is poorly responsive to supplemental  O2 and for which no  cardiac or respiratory cause can be found. Cyanosis decreases and disappears progessively when HbF is replaced by HbA.

Anesthetic implications:

keep that possibility in mind in case of unexplained neonatal cyanosis, not responding to oxygenotherapy: arterial blood gases ! Transcutaneous paO2 monitoring.

References : 

-        Charon A, Henrion E, Delpire S, Redondi A, Lecart C.
Cyanose néonatale due à une hémoglobine fœtale M-Osaka.
Arch Pédiatr 2011 ; 18 : 1107-9.

-        Alonso-Ojembarrena A, Lubian-Lopez SP.
Hemoglobin M disease as a cause of cyanosis in a newborn.
J Pediatr Hematol Oncol 2016; 38:173-5.

Updated: Januiary 2020