Abstract:

Two cases of rare α thalassemia gene mutation were reported. The results of blood routine showed the decreased mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), and the normal hemoglobin (Hb). Hemoglobin electrophoresis showed that the first patient had normal HbA2 and elevated HbF, and the second patient had normal HbA2 and HbF. Common mutations of α and β thalassemia gene were not detected in both patients. Because the blood phenotype and genotype did not match, the α thalassemia carriers were suspected. Three rare α thalassemia types, including--^THAI, -α^27.6 and -α^21.9, were further detected by Gap-PCR. However, the results did not show abnormality. Sanger sequencing method was then used to directly sequence the DNA of the study subjects. It was found that the two patients carried rare mutations of α globin gene, namely CD26 (GCG>GGG) heterozygous mutation and CD104 (TGC>TAC) heterozygous mutation, respectively. In this study, two rare α thalassemia gene mutations were reported, which enriched the gene mutation spectrum of the Chinese population, with a guiding significance for the screening diagnosis and genetic counseling of the disease.

Key words: Alpha-thalassemia, Genes, Mutation, Genetic testing, Case reports