A Novel Pathogenic β-Thalassemia Mutation Identified at Codon 8 (HBB: c.27delG) in a Bangladeshi Family Acquired De Novo.

In Bangladesh, the practice of β-thalassemia (β-thal) carrier screening and prenatal diagnosis (PND) by β-globin gene sequencing has been initiated to prevent the birth of affected children. The study aimed to describe a novel de novo mutation of the β-globin gene and its clinical implication. Out of 100 Bangladeshi β-thal carrier families, one patient with hematological and clinical features associated with β-thal and her parents were included. Molecular characterizations of β-globin gene mutations were performed by direct sequencing. A novel nucleotide deletion mutation at codon 8 in the first exon of the β-globin gene (HBB: c.27delG) was found in a 1-year-old child of the studied family in a heterozygous state along with common Hb E (HBB: c.79G>A). The mutation caused a frameshift to a new stop codon at codon 18 resulting in a β0-thal phenotype. The proband exhibited a β-thal intermedia (β-TI)-like genotype, however, showed β-thal major (β-TM)-like complications and was transfusion-dependent. Her mother had a profile consistent with the Hb E trait, while the father had normal hematological indices. Mutation analyses revealed the mother to be heterozygous for Hb E, while the father had a normal genotype. The novel mutation was assumed to be inherited de novo by the paternity test. The study documented a novel pathogenic mutation in the β-globin gene in a Bangladeshi family by β-globin gene sequencing.