Dominant β-thalassaemia with unusually high Hb A2 and Hb F caused by βCD121(−G) (HBB:c.364delG) in exon 3 of β-globin gene. Issue 8 (26th December 2019)

• Record Type: Journal Article
• Authors: Singha, Kritsada; Karnpean, Rossarin; Fucharoen, Goonnapa; Fucharoen, Supan
• Is Part Of: Journal of clinical pathology. Volume 73:Issue 8(2020)
• Page Start: 511
• Page End: 513
• Publication Date: 2019-12-26
• Subjects: genetics -- haematology -- haemoglobinopathy -- molecular genetics -- thalassaemia; Pathology -- Periodicals; Pathology, Molecular -- Periodicals; 616.0705
• DOI: 10.1136/jclinpath-2019-206308
• Languages: English
• ISSNs: 0021-9746

Abstract

Abstract : We describe a dominant β-thalassaemia caused by a deletion of G at nucleotide position 364 in exon 3 of the β-globin gene. The heterozygosity of this mutation was found in a 36-year-old Thai patient who had moderate hypochromic microcytic anaemia with haemolytic blood picture. Haemoglobin (Hb) analysis revealed relatively higher Hbs A2 (6.8%) and F (4.7%) as compared with those of β 0 -thalassaemia (n=278) and β + -thalassaemia (n=55) carriers in our series. Secondary structure prediction of the elongated β-globin chain showed that the α-helix at the C-terminal is disrupted dramatically by the random coil and β-sheet, which should result in a highly unstable β-globin variant, undetectable in peripheral blood and a dominant clinical phenotypic feature.