Molecular analysis of alpha‐ and beta‐thalassemia in Meizhou region and comparison of gene mutation spectrum with different regions of southern China

BACKGROUND: Thalassemia is a group of inherited autosomal recessive hemolytic anemia disease caused by reduced or absent synthesis of globin chain/chains of hemoglobin. Only few studies showed the molecular characterization of α‐ and β‐thalassemia in Meizhou city of China. METHODS: A total of 22,401 individuals were collected; hematological and hemoglobin electrophoresis analysis and thalassemia genetic testing were performed. RESULTS: Eleven thousand and thirty (49.24%) cases with microcytosis (mean corpuscular volume (MCV) < 82 fl), 11,074 (49.44%) cases with hypochromia (mean corpuscular Hb (MCH) < 27 pg) in 22,401 subjects, 11,085 cases with abnormal hemoglobin results were identified in subjects aged ≥6 months. 7,322 (32.69%) subjects harbored thalassemia mutations, including 4,841 (21.61%) subjects with α‐thalassemia, 2,237 (9.99%) with β‐thalassemia, and 244 (1.09%) with α‐thalassemia combined β‐thalassemia. 18 genotypes of α‐thalassemia mutations and 27 genotypes of β‐thalassemia mutations were characterized. The most frequent α gene mutation was ‐‐(SEA) (64.69%), followed by ‐α(3.7) (19.93%), ‐α(4.2) (7.73%), α(CS)α (3.97%), and α(WS)α (2.83%). The six most common β‐thalassemia mutations were IVS‐II‐654 (C>T) (39.79%), CD41‐42 (‐TCTT) (33.02%), −28 (A>G) (10.38%), CD17 (A>T) (9.08%), CD27‐28 (+C) (2.14%), and CD26 (G>A) (2.02%). In addition, MCV and MCH were sensitive markers for α‐ and β‐thalassemia except for ‐α(3.7)/αα, ‐α(4.2)/αα, α(CS)α/αα, α(WS)α/αα, and β(Cap+40−43)/β(N). CONCLUSIONS: The ‐‐(SEA), ‐α(3.7), and ‐α(4.2) deletions were the main mutations of α‐thalassemia, while IVS‐II‐654 (C>T), CD41‐42 (‐TCTT), −28 (A>G), and CD17 (A>T) mutations of β‐thalassemia in Meizhou. There were some differences in thalassemia mutation frequencies in Meizhou city from other populations in China.