A Novel Heme Pocket Hemoglobin Variant Associated with Normal Hematology: Hb Zara or α91(FG3)Leu→Ile (α2) (HBA2: c.274C > A).
We report a new hemoglobin (Hb) variant on the HBA2 gene, Hb Zara [α91(FG3)Leu→Ile (α2); HBA2: c.274C > A], which was found in a Caucasian man from Croatia. It was observed by routine cation exchange chromatography as an abnormal 21.8% fraction overlapping Hb A2, and associated with normal hematology. It was slightly unstable by the standard isopropanol precipitation test. DNA analysis revealed the CTT > ATT mutation at codon 91 on an α2 gene of a normal α-globin gene arrangement. This new variant represents the sixth described mutation at codon α91 and fourth on the α2 locus. As a result of the slight instability due to the significant role of the α91 residue in the α1β2 contact, the level of the Hb Zara variant was lower than levels observed for several stable variants codified by the α2 locus.
a Dipartimento di Scienze Biomediche , Università di Sassari , Sassari , Italia.
Sandro
S
Trova
a Dipartimento di Scienze Biomediche , Università di Sassari , Sassari , Italia.
Paolo
P
Mereu
a Dipartimento di Scienze Biomediche , Università di Sassari , Sassari , Italia.
Luca
L
Decandia
b Centro Trasfusionale e di Microcitemia di Olbia , Italia.
Elena
E
Cocco
a Dipartimento di Scienze Biomediche , Università di Sassari , Sassari , Italia.
Bruno
B
Masala
a Dipartimento di Scienze Biomediche , Università di Sassari , Sassari , Italia.
Laura
L
Manca
a Dipartimento di Scienze Biomediche , Università di Sassari , Sassari , Italia.
Monica
M
Pirastru
D000328:Adult; D000483:Alleles; D019943:Amino Acid Substitution; D006443:Hemoglobin A2 / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008297:Male; D009154:Mutation; D055542:alpha-Globins / Q000235:genetics; D017085:alpha-Thalassemia / Q000175:diagnosis / Q000235:genetics
D006455:Hemoglobins, Abnormal; D055542:alpha-Globins; D006443:Hemoglobin A2
Hb Zara; Hemoglobin (Hb) variant; heme pocket; α-Globin gene; α1β2 contact