A novel SNP rs11759328 on Rho GTPase-activating protein 18 gene is associated with the expression of Hb F in hemoglobin E-related disorders.

Hemoglobin (Hb) F has a modulatory effect on the clinical phenotype of ß-thalassemia disease. High expression of Hb F in Hb E-related disorders has been noted, but the mechanism is not well understood. We have examined the association of a novel SNP rs11759328 on ARHGAP 18 gene and other known modulators with a variability of Hb F in Hb E-related disorders. Genotyping of SNP rs11759328 (G/A) was performed based on high-resolution melting analysis. The rs11759328 (A allele) was shown to be significantly associated with Hb F levels (p < 0.05) in heterozygous and homozygous Hb E. High levels of Hb F in both heterozygous and homozygous Hb E were also found to be associated with SNPs in the study of other modifying genes including KLF 1 mutation, rs7482144 (Gγ-XmnI), rs4895441, rs9399137 of (HBS1L-MYB), and rs4671393 (BCL11A). Multivariate analysis showed that KLF1 mutation and SNP rs11759328 (GA) (ARHGAP18) modulated Hb F expression in heterozygous Hb E. For homozygous Hb E, this was found to be related to five modifying factors, i.e., KLF1 mutation, rs4895441 (GG), rs9399137 (CC), rs4671393 (AA), and rs4671393 (GA). These results indicate that a novel SNP rs11759328 is a genetically modifying factor associated with increased Hb F in Hb E disorder.