Level of Hemoglobin F and G gamma Gene Expression in Sickle Cell Disease and Their Association with Haplotype and Xmnl Polymorphic Site in South of Iran

Background: molecular genetic factors regulating hemoglobinf (hb f) expression are important modifiers of the severityof sickle cell anemia (ss).methods: the prevalence of xmni polymorphic site , the gy:ayratio and the hb f level were determined using pcr-rflp procedure,hplc and alkaline denaturation method, respectively, invar ious haplotypes of 52 pat ients with ss, 18 pat ients withsickle/li-thalassemia (s/thal), 17 with sickle cell trait (as) and53 normal subjects from fars and khuzestan provinces who attendedthe hematology research center, shiraz university ofmedical sciences, shiraz, iran during 2002-03.results: the prevalence of xmni (+/+) site in patients with sswas 53.8% which was higher than that for s/thal (23.5 %), as(22.2%) and normal individuals (7.5%). there was a correlationbetween the presence of xmni site and high gy : ~ ratio in ss ands/thal patients with arab-indian homozygous or heterozygoushaplotypes (contingency coefficient=0.43, p=0.002) . in the presentstudy, the hb f level was sign ificantly higher in ss patientswith one or two arab-ind ian haplotypes as compared to bantu ,benin and cameroon haplotypes. however, the hb f level wassignificantly higher in patients with s/thal having two xmnlsites carrying arab-indian and senegal haplotypes as comparedto bantu , benin and cameroon haplotypes. the increasing effectof presence xmni s ite on hb f level appears only when hemolyticstress is present as in ss and s/thal patients (contingenc gamma coefficient=0.35, p=0.01).conclusion: th e presence of xmni polymorphic s ite in haplotypeback grounds of arab-indian and senegal in sickle cellanemia is corre lated with high level of hb f and g gamma:ay rat io.