title: Elevated Hb A₂ Levels in a Patient with a Compound Heterozygosity for the (β⁺) -31 (A > G) and (β⁰) Codon 17 (A > T) Mutations Together with a Single α-Globin Gene.
abstract: We report the molecular and hematological feature of a Thai woman who had clinical diagnosis of β-thalassemia intermedia (β-TI). Hemoglobin (Hb) high performance liquid chromatography (HPLC) analysis identified Hb A (64.4%), Hb F (12.3%) and Hb A2/E (15.9%) with small peaks of Hb Bart's (γ4) and Hb H (β4). She was initially diagnosed as EA Bart's disease, which occurs from combination of Hb H disease and Hb E (HBB: c.79G > A) trait. However, the Hb analysis using capillary electrophoresis (CE) demonstrated no Hb E, 68.5% Hb A, 15.5% Hb F and 16.0% Hb A2. DNA analysis showed a compound heterozygosity for (β(+)) -31 (A > G) (HBB: c.-81A > G) and (β(0)) codon 17 (A > T) (HBB: c.52A > T) mutations and deletional Hb H (- -(SEA)/-α(3.7)). Thus, she was finally diagnosed with a combination of Hb H disease and compound heterozygosity of β(+)/β(0)-thalassemia (β(+)/β(0)-thal). The β-globin mutations could affect not only hematological parameters but also elevate the Hb A2 levels. These effects could not be ameliorated by the coinheritance of Hb H disease. Therefore, a better understanding of the effects of this combination on hematological analysis data will be useful for providing accurate diagnosis, genetic counseling, prevention and control programs of β-thalassemia major (β-TM).
authors.affiliation: School of Allied Health Sciences, University of Phayao , Phayao , Thailand.
authors.forename: Sitthichai
authors.initials: S
authors.lastname: Panyasai
authors.forename: Kanokwan
authors.initials: K
authors.lastname: Jaiping
authors.forename: Sakorn
authors.initials: S
authors.lastname: Pornprasert
mesh_terms: D000293:Adolescent; D003062:Codon; D004252:DNA Mutational Analysis; D004909:Erythrocyte Indices; D005260:Female; D005838:Genotype; D006443:Hemoglobin A2 / Q000235:genetics* / Q000378:metabolism*; D006579:Heterozygote; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D055542:alpha-Globins / Q000235:genetics*; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000097:blood / Q000175:diagnosis / Q000235:genetics
chemical_list: D003062:Codon; D055542:alpha-Globins; D055544:beta-Globins; D006443:Hemoglobin A2
keywords: Hb A2; codon 17 (A > T) (HBB: c.52A > T); β+-Thalassemia (β+-thal); β0-thalassemia (β0-thal); −31 (A > G) (HBB: c.-81A > G)