Rare β-globin gene Codon 24 (GGT>GGA) mutation causing β-thalassemia: a case report and literature analysis

Objective: To study the mutation types, hematological characteristics and clinical manifestations of rare β-globin gene. Methods: A total of 120 suspected cases of β-thalassemia were collected. The whole blood cells were classified and counted, and hemoglobin (Hb) was analyzed by electrophoresis for all the cases.The mutation types of α-and β-globin genes were analyzed by cross break point PCR, fluorescence PCR melting curve analysis and DNA sequencing. Results: A total of 120 cases of β-thalassemia were detected, of which 1 case was a rare mutation of β-globin gene, and the genotype was Codon 24 (GGT> GGA, HBB:c.75T> A) heterozygote. The case was a 39-year-old male, and the routine blood test showed the following results:Hb 127.3 g/L, red blood cell (RBC) 5.81x10¹²/L, mean corpuscular volume (MCV) 70.29 fL, mean corpuscular haemoglobin (MCH) 21.94 pg and mean corpuscular hemoglobin concentration (MCHC) 312.10 g/L. Hb analysis showed that Hb A₂ was 4.5% and Hb F was 0.4%.The α-thalassemia genetic analysis did not identify common types of mutations. Conclusion: The rare β-globin gene Codon 24 (GGT> GGA, HBB:c.75T> A) mutation causing β-thalassemia is found in China for the first time. This type of case is clinically prone to misdiagnosis and should be given more attention.