First description of the rs45496295 polymorphism of the C/EBPE gene in β-thalassemia intermedia patients.

The C/EBPE gene, located in 14q11.2, encodes for a B/zip-type transcription factor. The C/EBPɛ is involved in terminal differentiation and functional maturity of granulocyte progenitor cells and in cell apoptosis during myeloid differentiation. A C/EBPE gene has recently been described as a candidate gene involved in clinical variability of β-thalassemia (β-thal). In this study, the C/EBPE gene was sequenced in 146 subjects divided into the severe type of β-thal major (β-TM) and moderate type of β-thal intermedia (β-TI), and a control group. The analysis identified the rs45496295 (C > T) polymorphism in the heterozygous state in 73.9% β-TI patients, which was not the case in the β-TM patients or in the control group. Thus, the T allele is consequently associated with the β-TI group (p = 10(-3)). According to the Human Splicing Finder (version 3.0, Marseille, France), the presence of the rs45496295 polymorphism leads the creation of a new intronic exotic splicing enhancer (ESE) site. Moreover, the T allele of rs45496295 is associated with a lower transfusion regimen (p = 10(-3)) and a higher pretransfusion hemoglobin (Hb) rate (p = .006). The comparison of several factors concerning T allele carriers and non-carriers showed that the T allele does not act on the Hb F rate. The T allele of rs45496295, associated with moderate type of β-thal, seems to modify the C/EBPɛ action, thereby preventing the hemolysis.