Singha K, Karnpean R, Fucharoen G, Fucharoen S. Dominant β-thalassaemia with unusually high Hb A
2 and Hb F caused by β
CD121(-G) (HBB:c.364delG) in exon 3 of β-globin gene.
J Clin Pathol 2019;
73:511-513. [PMID:
31879269 DOI:
10.1136/jclinpath-2019-206308]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/07/2019] [Accepted: 12/13/2019] [Indexed: 11/03/2022]
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 β0-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.
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