Hb M-Iwate in an Indian family.
BACKGROUND
High performance liquid chromatography in a newborn girl with congenital cyanosis and a unilateral cleft palate revealed a variant hemoglobin with retention time of 4.8 min, similar to hemoglobin Q-India. Since hemoglobin Q-India did not explain the cyanosis, further investigations were initiated.


METHODS
Sequencing of α-globin genes revealed hemoglobin M-Iwate ([α87 (F8) His → Tyr]) that was confirmed on restriction enzyme analysis.


RESULTS
Hemoglobin M-Iwate is a rare methemoglobinemic variant formed due to a point mutation in the α-globin gene. Primarily reported from the Iwate prefecture of Japan, there have been occasional case reports from other regions as well. Inherited methemoglobinemia finds only rare mention in Indian literature while hemoglobin M-Iwate has not been reported from India.


CONCLUSIONS
This case illustrates the step-wise logical diagnostic approaches necessary to elucidate the cause of methemoglobinemia in an otherwise healthy child with cyanosis.
Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Ganesh V
GV
Kumar
Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Prashant
P
Sharma
Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Sanjeev
S
Chhabra
Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Jasbir Kaur
JK
Hira
Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Amita
A
Trehan
Department of Hematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Electronic address: reenadaspgi@hotmail.com.
Reena
R
Das
D019943:Amino Acid Substitution; D002972:Cleft Palate / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D003490:Cyanosis / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006449:Hemoglobin M / Q000235:genetics*; D006639:Histidine / Q000378:metabolism; D006801:Humans; D007194:India; D007231:Infant, Newborn; D008708:Methemoglobinemia / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D017354:Point Mutation; D014443:Tyrosine / Q000378:metabolism; D055542:alpha-Globins / Q000235:genetics*
D055542:alpha-Globins; D014443:Tyrosine; D006639:Histidine; C027542:hemoglobin M Iwate; D006449:Hemoglobin M
Alpha globin variant; Congenital cyanosis; Gene sequencing; Hemoglobin M-Iwate; Methemoglobin; Polymerase chain reaction restriction fragment length polymorphism