The Clinical Researching On The B Thalassemia Mutation IVS-â…¡-5 Gâ†'C

Objective:To investigate the clinical and laboratorial features of the β-thalassemia mutation IVS-II-5 Gâ†'C.Methods:Cases admitted to the First Affiliated Hospital of Guangxi Medical University from July 2013 to July 2014 were subjected to this study. Hematologic analyses, hemoglobin analyses by high performance liquid chromatography (HPLC) were performed to the cases. Genotyping were analyzed by reverse dot blot hybridization (RDB) and DNA sequencing.Results:1. Among 51 cases with unknown mutations,12 cases were identified as heterozygotes with IVS-II-5 Gâ†'C mutation. The cases aged from 1 to 34 years old, including 5 males and 7 females.2. The haematological examination showed that 8 heterozygotes with β IVS-II-5 Gâ†'C mutation had hemoglobin (Hb) level from 91.8～146.8 g/L, while mean corpuscular volume (MCV) were 64.65 to 109 β and mean corpuscular hemoglobin (MCH) were 20.78 to 36.17 pg.4 double heterozygotes for β IVS-II-5 Gâ†'C mutation and other β thalassemia mutation had hemoglobin (Hb) level from 57.6～89.5 g/L, while mean corpuscular volume (MCV) were 59.14 to 68.37 fL and mean corpuscular hemoglobin (MCH) were 16.66 to 21.38 pg.3. Hemoglobin analysis showed that among 8 heterozygotes β IVS-â…¡-5 Gâ†'C mutation,5 had normal Hb F and Hb A2 level ranged from 3.5 to 3.9%,2 had normal Hb A2 and Hb F value, while 1 had normal Hb A2 value but Hb F value reached 8.9%. The case with double heterozygotes for β IVS-â…¡-5 Gâ†'C mutation and β CD71/72 mutation had Hb A2 for 6.0% and Hb F for 23.9%. The case with double heterozygotes for P IVS-â…¡-5 Gâ†'C mutation and β CD17 mutation had Hb A2 for 6.7% and Hb F for 27%. Two cases with double heterozygotes for β IVS-II-5 G-+C mutation and β CD41/42 mutation had Hb A2 for for 4.3% and 6.2%, Hb F for 31.4% and 25.1%.4. β thalassemia genotyping showed 12 cases were P IVS-II-5 Gâ†'C heterozygotes or co-inheritance with other β-thalassemia mutations, including 8 heterozygotes (pIVS-â…¡-5/pN) and 4 double heterozygotes. The latter were 1 for βCD71/72/βIVS-â…¡-5,1 for βCD17/βIVS-â…¡-5,and 2 for βCD41/42/βIVS-â…¡-5 respectively.5. Among the 8 heterozygotes with β IVS-â…¡-5 Gâ†'C mutation,2 cases had mild anemia. The rest 6 cases had no clinical symptoms. The case with double heterozygotes for β IVS-â…¡-5 Gâ†'C mutation and p CD71/72 mutation showed severe anemia. The case with double heterozygotes for β IVS-â…¡-5 Gâ†'C mutation and β CD 17 mutation showed moderate anemia.2 case with double heterozygote for β IVS-â…¡-5 Gâ†'C mutation and β CD41/42 mutation showed moderate to severe anemia.Conclusion:1. The mutation of β globin gene IVS-â…¡-5 Gâ†'C causes P+thalassemia.2. The heterozygotes with β IVS-â…¡-5 Gâ†'C mutation may have no clinical symptoms or had mild anemia. In some cases the haematological examinations were normal, which may cause misdiagnosis in clinical practice.3. Double heterozygote for β IVS-II-5 Gâ†'C mutation and other β globin gene mutations showed moderate or severe anemia.4. This is the first report that the heterozygotes with β IVS-II-5 Gâ†'C mutation may have normal values of Hb A2 and Hb F, or only have elevated Hb F, which may cause misdiagnosis easily.