Co-inheritance of α
0 -thalassemia elevates Hb A
2 level in homozygous Hb E: Diagnostic implications.
Int J Lab Hematol 2017;
39:508-512. [PMID:
28497611 DOI:
10.1111/ijlh.12677]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 03/02/2017] [Indexed: 11/29/2022]
Abstract
INTRODUCTION
Differentiation of homozygous hemoglobin (Hb) E with and without α0 -thalassemia is subtle on routine hematological ground. We examined in a large cohort of homozygous Hb E if the level of Hb A2 is helpful.
METHODS
A total of 592 subjects with homozygous Hb E were recruited from ongoing thalassemia screening program. Additionally, five couples at risk of having fetuses with Hb Bart's hydrops fetalis who were homozygous Hb E were also investigated. Hb analysis was performed using capillary electrophoresis system. Globin genotypes were defined by DNA analysis.
RESULTS
Subjects were classified into four groups including pure homozygous Hb E (n=532), homozygous Hb E/α0 -thalassemia (n=48), Hb Constant Spring EE Bart's disease (n=8), and Hb EE Bart's disease (n=4). The levels of Hb A2 were found, respectively, to be 4.97±0.69, 6.64±1.02, 4.86±0.87, and 7.60±1.04%. Among five couples at risk, α0 -thalassemia was identified in three subjects with Hb A2 >6.0%.
CONCLUSIONS
Increased Hb A2 level is a useful marker for differentiation of homozygous Hb E with and without α0 -thalassemia. This should lead to a significant reduction in number of referral cases of homozygous Hb E for molecular testing of α0 -thalassemia in routine practice.
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