Co-Inheritance of Heterozygous β⁰-Thalassemia with Single Functional α-Globin Gene: Challenges of Carrier Detection in Pre-Marital Screening Program for Thalassemia

Abstract

This is a report of a couple with abnormal hematological indices who were investigated for α & β-thalassemia mutations. Based on CBC and capillary hemoglobin electrophoresis results, the male and female subjects were β & α-thalassemia carriers, respectively. Multiplex-Gap-PCR and Sanger sequencing techniques were used for the identification of mutations on α and β-globin genes. The DNA test showed the presence of c.315 + 1 G > A mutation on β-globin gene of male subject while the female case had – MED double gene deletion and c.427T > C mutation on α-globin and, interestingly, she was also a carrier for c.315 + 1 G > A mutation on β-globin gene. Cases with the coinheritance of heterozygous β0-thalassemia with one functional α-globin gene have normal HbA2 levels that may lead to their being misdiagnosed as β-thalassemia carriers, especially in premarital screening programs for thalassemia. Therefore, β-globin gene sequencing is recommended in cases with normal Hb electrophoresis and reduced hematological indices in premarital screening programs for thalassemia, especially in regions with a high frequency of β-globin mutations, in order to identify all the β-thalassemia carriers.

Keywords

• β-thalassemia
• α-thalassemia
• premarital screening program