A new δ chain variant, Hb A2-Tunis [δ46(CD5)Gly → Glu; HBD: c.140G>A], observed in a Tunisian family in association with a compound heterozygosity for Hb C [β6(A3)Glu → Lys; HBB: c.19G>A] β(0)-thalassemia [IVS-I-1 (β143, G>A); HBB: c.92+1G>A].
We describe a new δ-globin variant, Hb A2-Tunis [δ46(CD5)Gly → Glu; HBD: c.140G>A]. This hemoglobin (Hb) variant displayed a faster electrophoretic mobility than normal Hb A2 and was expressed at 3.2%. The molecular defect was characterized by DNA sequencing analysis. Hb A2-Tunis was found in a carrier of a β(0)-thalassemia (β(0)-thal) [IVS I-1 (β143, G>A); HBB: c.92 + 1G>A] and Hb C [β6(A3)Glu → Lys; HBB: c.19G>A], presenting with a normal Hb A2 level. Phenotype and genotype investigations revealed that the patient has a total Hb A2 level of 7.1% that was expected for a β-thalassemia (β-thal) minor carrier.
Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur , Tunis , Tunisie.
Imen
I
Moumni
Amine
A
Zorai
Sonia
S
Mahjoub
Ikbel
I
Mosbahi
Dorra
D
Chaouechi
Neila
N
Benromdhane
Salem
S
Abbes
D000328:Adult; D000368:Aged; D001483:Base Sequence; D004252:DNA Mutational Analysis; D005192:Family Health; D005260:Female; D005838:Genotype; D018698:Glutamic Acid / Q000235:genetics; D005998:Glycine / Q000235:genetics; D006443:Hemoglobin A2 / Q000235:genetics*; D006444:Hemoglobin C / Q000235:genetics; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D017354:Point Mutation; D014416:Tunisia; D055544:beta-Globins / Q000235:genetics; D017086:beta-Thalassemia / Q000235:genetics; D055546:delta-Globins / Q000235:genetics*
D006455:Hemoglobins, Abnormal; D055544:beta-Globins; D055546:delta-Globins; C000593192:hemoglobin A2-Tunis; D018698:Glutamic Acid; D006444:Hemoglobin C; D006443:Hemoglobin A2; D005998:Glycine