Analysis of clinical phenotype of a α2-globin gene mutation -IVS-Ⅱ-55 (T→G) / 临床检验杂志

Objective@#To identify a α-globin gene mutation-IVS-Ⅱ-55 (T→A) and analyze hematological characteristics of IVS-Ⅱ-55 (T→G) carriers. @*Methods@#The peripheral blood samples were collected from the members of five family and three sporadic IVS-Ⅱ-55(T→G) carriers for the analysis of RBC parameters and hemoglobin electrophoresis. Gap-PCR, PCR-RDB (reverse dot blot) and DNA sequencing were carried out for the identification of gene deletion and mutation of α-globin and β-globin. @*Results@#The results of RBC parameters of five infant probands which presented with microcytic hypochromic anemia were below the normal reference interval. One of the adult carriers of IVS-Ⅱ-55 (T→G) heterozygote alone presented with microcytic hypochromic anemia, and the others showed normal RBC parameters. The hematological phenotype index (MCV, MCH and HbA 2 ) of one adult carrying a compound heterozygote for IVS-Ⅱ-55 (T→G) and βCD27-28M/N were 65.0 fL, 20.3 pg and 5.8% respectively. The hematological phenotype index (MCV, MCH, HbA 2 and HbF) of one adult carrying a compound heterozygote for IVS-Ⅱ-55 (T→G) and SEA-HPFH were 81.9 fL, 26.5 pg, 3.0% and 29.0% respectively. The HbA 2 levels of all carriers of IVS-Ⅱ-55 (T→G) heterozygote alone were in normal range. No abnormal hemoglobin band was detectable on hemoglobin electrophoresis for all the carries. @*Conclusion@#The carriers of IVS-Ⅱ-55(T→G) heterozygote alone were asymptomatic. The phenotype of compound heterozygote for β-thalassemia was similar to that of β-thalassemia alone.