Coinheritance of Hb A2-Melbourne (HBD: c.130G>A) and Hb E (HBB: c.79G>A) in Laos and Simultaneous High Resolution Melt Detection of Hb A2-Melbourne and Hb A2-Lampang (HBD: c.142G>A) in a Single Tube |
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Authors: | Wittaya Jomoui Prapaporn Panichchob Punchita Rujirachaivej Sitthichai Panyasai Wanicha Tepakhan |
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Affiliation: | 1. Department of Pathology, Maha Chakri Sirindhorn Medical Center, Faculty of Medicine, Srinakharinwirot University, Ongkharak, Nakhon Nayok, Thailand;2. wittayaj@g.swu.ac.th;4. Department of Medical Technology, School of Allied Health Sciences, University of Phayao, Phayao, Thailand;5. Department of Pathology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand |
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Abstract: | AbstractWe report the molecular and hematological identifications of a Hb A2 variant [coinheritance of Hb A2-Melbourne (HBD: c.130G>A) and Hb E (HBB: c.79G>A)] found for the first time in the Lao People’s Democratic Republic (PDR). The subject was a 29-year-old pregnant Laotian woman who was a foreign worker in Thailand and was diagnosed with thalassemia and hemoglobinopathies. Capillary electrophoresis (CE) demonstrated 1.6% of Hb A2, with a minor unknown peak at the initial Z1 zone (1.7%). Identification of abnormal hemoglobin (Hb) using direct DNA sequencing showed a genetic defect causing a δ-globin gene missense mutation at codon 43 (GAG>AAG) causing a glutamic acid to lysine substitution corresponding to Hb A2-Melbourne. The origin of Hb A2-Melbourne in Lao PDR may be similar to a case found in Thailand with the [+ –?– –?– + +] haplotype. We developed a method that could clearly detect Hb A2-Melbourne and Hb A2-Lampang (HBD: c.142G>A) mutations in a single tube using high resolution melt (HRM) analysis. The HRM analysis is a more effective method for rapid detection than conventional polymerase chain reaction (PCR), as there is no need for a post-PCR step, and no exposure to ethidium bromide. This new method would be a useful addition for the first investigation of a suspected Hb A2 variant in the routine molecular setting. |
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Keywords: | δ-Globin gene mutation Hb A2-Melbourne hemoglobin (Hb) variant high resolution melt (HRM) analysis |
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