Co-inheritance of the Hb Sun Prairie mutation with a point mutation at 5'-UTR in the eastern Indian population.

Summary Haemoglobin (Hb) Sun Prairie (α2-globin cd130, GCTCCT, AlaPro) is detected in three unrelated chromosomes, in association with a CT transition in the 5′-untranslated region (UTR), two bases upstream from the translation start site. Reported inversion of α/β-mRNA ratio observed in Hb Sun Prairie mutants might stem from the second mutation and should be investigated. Molecular modelling studies indicate that the 130th residue of α-globin faces primarily the central cavity of the molecule and is not in contact with any β-chain residue; further, no significant disruption of the Hb structure because of the Sun Prairie mutation is discernible. Depression of translation because of the second mutation of a conserved base in the 5′-UTR might explain the observed clinical severity.