A Rare Alpha-Globin Mutation: Detailed Analysis of the Hb Rogliano Variant (α1 Cod 108 Thr→Asn)

Area of Science:

• Genetics
• Molecular Biology
• Hematology

Background:

• Alpha-thalassemia results from reduced alpha-globin chain synthesis, often due to gene deletions.
• Non-deletional variants contribute to disease heterogeneity but are less common.
• Long-read sequencing enhances analysis of complex genomic regions like HBA1 and HBA2.

Purpose of the Study:

• To evaluate the utility of long-read sequencing for identifying alpha-globin gene variants.
• To characterize rare non-deletional alpha-globin variants.
• To report the first case of Hb Rogliano in Indonesia.

Main Methods:

• Targeted long-range PCR amplification of HBA1 and HBA2 genes.
• Long-read sequencing using the Oxford Nanopore PromethION 24 platform.
• Bioinformatic analysis and visualization with IGV.

Main Results:

• Achieved high sequencing depth (>390x) for reliable variant detection.
• Identified five variants in HBA1 and HBA2 genes.
• Classified HBA1:c.326C>A (p.Thr108Asn; Hb Rogliano) as likely pathogenic; others as benign/likely benign.

Conclusions:

• Long-read sequencing is a powerful tool for characterizing complex alpha-globin variants.
• This study reports the first case of Hb Rogliano in Indonesia.
• The findings contribute to understanding the molecular basis of alpha-thalassemia.