Table 1.
Common types of beta-thalassemia: severity and ethnic distribution.
| Population | β-gene mutation | Severity |
|---|---|---|
| Indian | -619 del | β0 |
| Mediterranean | -101 C→T | β++ |
| Black | -88 C→T | β++ |
| Mediterranean; African | -87 C→G | β++ |
| Japanese | -31 A→G | β++ |
| African | -29 A→G | β++ |
| Southeast Asian | -28 A→C | β++ |
| Mediterranean; Asian Indian | IVS1-nt1 G→A | β0 |
| East Asian; Asian Indian | IVS1-nt5 G→C | β0 |
| Mediterranean | IVS1-nt6 T→C | β+/++ |
| Mediterranean | IVS1-nt110 G→A | β+ |
| Chinese | IVS2-nt654 C→T | β+ |
| Mediterranean | IVS2-nt745 C→G | β+ |
| Mediterranean | codon 39 C→T | β0 |
| Mediterranean | codon 5 -CT | β0 |
| Mediterranean; African-American | codon 6 -A | β0 |
| Southeast Asian | codon 41/42 -TTCT | β0 |
| African-American | AATAAA to AACAAA | β++ |
| Mediterranean | AATAAA to AATGAA | β++ |
| Mediterranean | codon 27 G→T Hb (Hb Knossos) | β++ |
| Southeast Asian | codon 79 G>A (Hb E) | β++ |
| Malaysia | Codon 19 G>A (Hb Malay) | |
β0:complete absence of beta globin on the affected allele
β+:residual production of beta globin (around 10%)
β++:very mild reduction in beta globin production