Genetic heterogeneity of hemoglobin AEBart's disease: A large cohort data from a single referral center in northeast Thailand

AEBart's disease is a thalassemia intermedia usually characterized by the interaction of alpha degrees-thalassemia with either deletional or non-deletional alpha(+)-thalassemia in Hb E heterozygote. Genotypic and phenotypic features are heterogeneous. We studied the hematologic and molecular characteristics of this disease in a cohort of 173 Thai patients encountered at our center in northeast Thailand. Hemoglobin and DNA analyses identified patients with deletional AEBart's disease (n = 84), Hb Constant Spring AEBart's disease (n = 81), Hb Pakse-AEBart's disease (n = 5), AEBart's disease with codon 30 mutation (n = 1) and two hitherto un-described forms of AEBart's disease due to interaction of Hb E heterozygote and alpha degrees-thalassemia with the -alpha(16.6) kb deletional alpha(+)-thalassemia (n = 1) and Hb Q-Thailand (n = 1). Different phenotypic expression of these AEBart's diseases with low Hb, Hct and MCV and increased RDW values with marked reduction in Hb E levels were observed. It was found that all these forms of AEBart's disease showed similar thalassemia intermedia phenotypes but those with non-deletional forms were relatively more anemic. Our data confirm that in such area with high prevalence of hemoglobinopathies such as Southeast Asia, identification of rare thalassemia alleles in a thalassemia intermedia patient should not be ignored. Careful consideration of different phenotypic expression may help in providing presumptive diagnosis of this disease where access to molecular testing is limited. However, molecular diagnostic is useful for predicting the clinical outcome and improving genetic counseling of these complex hemoglobinopathies. (c) 2013 Elsevier Inc. All rights reserved.