First Report of a Dominantly Inherited β-Thalassemia Caused by a Novel Elongated β-Globin Chain

Abstract

A distinct set of mutations on the β-globin gene leads to dominantly inherited β-thalassemia (β-thal) that is associated with a disease phenotype in a single mutant copy. We described molecular and hematological characteristics of a novel elongated β-globin chain in combination with a known hemoglobin (Hb) variant (N-Baltimore or HBB: c.286A>G) in cis. The highly unstable Hb variant caused typical features of β-thal major (β-TM) or β-thal intermedia (β-TI) in two members of a family depending on their α-globin genotypes. The β mutant allele of the mother was transmitted in an autosomal dominant fashion to her daughter. They resemble severe forms of β-thal due to ineffective erythropoiesis. Taken together with previously published data, this result indicates that a dominant form of β-thal should be regarded as a phenotypic term of hemoglobinopathies caused by β chain variants that are highly unstable.

• α-Globin genes
• dominantly inherited β-thalassemia (β-thal)
• erythropoiesis

Acknowledgments

The authors would like to thank all their colleagues in Molecular Department of Kariminejad-Najmabadi Pathology and Genetics Center, Tehran, Iran, for valuable technical assistance and appreciate the cooperation of the patients taking part in this study.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.