Hanart C, Singha K, Changtrakul Y, Fucharoen S, Srivorakun H. Prospective screening for δ-hemoglobinopathies associated with decreased hemoglobin A
2 levels or hemoglobin A
2 variants: A single center experience.
Clin Chim Acta 2023:117417. [PMID:
37276945 DOI:
10.1016/j.cca.2023.117417]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/15/2023] [Accepted: 06/01/2023] [Indexed: 06/07/2023]
Abstract
BACKGROUND
δ-hemoglobinopathies may lead to misdiagnosis of several thalassemia syndromes especially β-thalassaemia carrier, it is important to evaluate the δ-globin gene defects in areas with high prevalence of globin gene disorders. We describe a prospective screening for δ-hemoglobinopathies in a routine setting in Thailand.
METHODS
Study was done on a cohort of 8,471 subjects referred for thalassemia screening, 317 (3.7%) were suspected of having δ-globin gene defects due to reduced hemoglobin (Hb) A2 levels and/or appearance of Hb A2-variants on hemoglobin analysis. Hematologic and DNA analysis by PCR and related assays were carried out.
RESULTS
DNA analysis of δ-globin gene identified seven different δ-globin mutations in 24 of 317 subjects (7.6%). Both known mutations; δ-77(T>C) (n=3), δ-68(C>T) (n=1), δ-44(G>A) (n=8), Hb A2-Melbourne (n=5), δIVSII-897(A>C) (n=5), and Hb A2-Troodos (n=1) and a novel mutation; the Hb A2-Roi-Et (n=1) were identified. This Hb A2-Roi-Et, results from a double mutations in-cis, δCD82(AAG>AAT) and δCD133(GTG>ATG), was interestingly found in combination with an in trans, 12.6 kb deletional δβ0-thalassemia in an adult Thai woman who had no Hb A2 and elevated Hb F. A multiplex-allele-specific PCR was developed to detect these novel δ-globin gene defects.
CONCLUSIONS
The result confirms a diverse heterogeneity of δ-hemoglobinopathies in Thailand which should prove useful in a prevention and control program of thalassemia in the region.
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