Detection of a Hb A2‐Melbourne (HBD: c.130G>A) combined with β‐thalassemia in a Chinese individual

• Published in: Journal of clinical laboratory analysis 2020-09, Vol.34 (9), p.e23401-n/a
• Main Authors: Li, Youqiong, Huang, Tongfeng, Mao, Tian, Zhang, Xiuqun, Liang, Liang, Meng, Menghui
• Format: Article
• Language: English
• Subjects: Brief Report; capillary electrophoresis (CE); Hb A2‐Melbourne; high‐performance liquid chromatography (HPLC); thalassemia; δ‐globin gene mutation
• ISSN: 0887-8013; 1098-2825; 1098-2825
• DOI: 10.1002/jcla.23401

Background Thalassemia is common in Southeast Asian countries, including China. Hb A2‐Melbourne is a rare hemoglobin variant and has never been reported in China. Here, we report a Hb A2‐Melbourne combined with β‐thalassemia in Chinese individuals which is the second case described in the published reports. Methods Complete blood counts (CBC) of a 28‐year‐old female showed signs of thalassemia during a routine screening. Hemoglobin analysis was subsequently performed using capillary electrophoresis (CE) and high‐performance liquid chromatography (HPLC). Four common deletional α‐thalassemia detection was carried out using a gap‐polymerase chain reaction (PCR). PCR and reverse dot‐blot were used to detect three non‐deletional α‐thalassemia and 17 types of point mutations in β‐thalassemia. Finally, it was identified by Sanger sequencing. Her husband also had CBC, hemoglobin analysis, and genetic diagnosis. Results CBC of the couple showed Hb 103 and 139 g/L, mean corpuscular volume 58 and 63.1 fL, mean corpuscular hemoglobin 19.7 and 20.4 pg, respectively. Hemoglobin analysis revealed Hb X 2.4%, Hb A2 2.8% by CE and Hb X 2.9%, Hb A2 2.4% by HPLC in the female. The results of her husband were Hb A93.5%, Hb A2 5.7%, Hb F 0.8% by CE. Genetic analysis of both spouses detected the same CD 41/42 mutations in β‐globin gene. Sanger sequencing of female identified a mutation of the δ‐globin gene (HBD:c.130G>A), corresponding to Hb A2‐Melbourne. Conclusion Hb A2‐Melbourne can lead to misdiagnosis of β‐thalassemia. δ‐globin gene mutation must be carefully examined in routine thalassemia screening.