Some quantitative trait loci (QTL) have been identified as important determinants for increase in HbF levels in SCD patients such as HMIP locus on chromosome 6, the BCL11A locus on chromosome 2, the Xp22.2 region of the X chromosome and the 8q region on chromosome 8 and more recently KLF1 locus34. Here, KLF1 is linked to Schnyder corneal dystrophy.