Two Novel δ-Globin Chain Variants Identified in the Chinese Population

Area of Science:

• Genetics
• Molecular Biology
• Hematology

Background:

• The HBD gene encodes the delta-globin chain, a component of Hemoglobin A2 (HbA2).
• HbA2 plays a role in red blood cell function, and its variants can have clinical implications.

Purpose of the Study:

• To identify and characterize novel mutations in the HBD gene within the Chinese population.
• To investigate the impact of these mutations on HbA2 levels and red blood cell parameters.

Main Methods:

• Sanger sequencing was employed to detect mutations in the HBD gene.
• Capillary electrophoresis was used for hemoglobin analysis, quantifying HbA2 levels and variant percentages.
• Red blood cell indices, including mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), were assessed.

Main Results:

• Two novel HBD mutations, c.349C>A (Arg>Ser) and c.201G>C (Lys>Asn), were identified.
• These mutations resulted in reduced HbA2 levels (1.2%) with corresponding variant percentages of 0.5% and 0.7%.
• Neither mutation was associated with significant changes in MCV or MCH, indicating no impact on red blood cell size or hemoglobin content.

Conclusions:

• The study reports two new HBD variants, HbA2-Shenzhen and HbA2-Zhanjiang, in the Chinese population.
• These variants lead to decreased HbA2 levels but do not appear to cause microcytosis or affect hemoglobin content per cell.
• Further research is warranted to understand the long-term clinical significance of these novel HBD mutations.