A Rare Heterozygote with a Novel IVS-Ⅱ-786 (T>A) Mutation on β-Globin Gene in a Patient with Thalassemia

Thalassemia is an inherited hemolytic blood disease, whose pathogenesis is an imbalance in the expression of hemoglobin. We report a case of a rare β-globin gene intron mutation for thalassemia patient.

The blood routine test was performed with an automatic blood cell analyzer. Hb analysis was conducted by hemoglobin (Hb) analyzer. The common β-thalassemia and α-thalassemia gene mutations were detected by Gap-PCR and fluorescence PCR melting curve, and the rare β-thalassemia gene mutations were detected by DNA sequencing.

A rare heterozygous mutation of β-globin gene IVS-II-786 (T>A) was found in this case. Blood routine analysis showed the following values: Hb 92 g/L, RBC 4.1 x 1012/L, MCV 74.10 fL, MCH 22.4 pg, MCHC 303 g/L, HCT 0.304 L/L, and RET-He 22.7 pg. Hemoglobin analysis showed values of HbA2 2.2% and HbF < 2% by automatic capillary electrophoresis. The results of gene analysis and DNA sequencing showed that the β-globin gene IVS-II-786 (T>A) mutation was heterozygous.

The heterozygote of β-globin gene IVS-II-786 (T>A) mutation was detected for the first time, and the clinical manifestation was moderate anemia. Hemoglobin analysis indicated that the level of HbA2 was decreased. This mutation is relatively rare and easy to misdiagnose in clinical practice. It will provide a new type of evidence and guidance for genetic counseling and clinical treatment of beta thalassemia.