Beta Thalassemia Mutation Distribution Atlas

Global Distribution of β-Thalassemia Mutations

Over 350 pathogenic variants of the HBB gene are known, yet ~20 mutations account for more than 80% of cases worldwide, showing strong regional clustering and founder effects.

Regional Hotspots:

• South Asia → IVS-I-5 (G>C)
• Mediterranean → IVS-II-1 (G>A)
• Southeast Asia → HbE (Cd26)

Migration and intermarriage continue to shift these patterns.

The data, compiled from Rao et al., Gene (2024) along with HbVar and IthaGenes, integrates studies from screening programs, patient cohorts, and published reports—making it a reliable reference but not a perfect reflection of population-level prevalence.

Mutation Mechanisms:

• Transcription defects → common in Mediterranean & Middle East
• RNA splicing defects → dominate South & East Asia
• Polyadenylation/3′ UTR changes → found in Mediterranean, Africa, Asia
• Translation defects (nonsense, frameshift, start codon) → globally spread

This diversity explains the wide spectrum of β-thalassemia severity, from silent carriers to severe β⁰-thalassemia.

The interactive map allows users to explore how mutation classes intersect with geography, providing a practical tool for genetic counseling, screening panel design, and clinical practice.