title: Genotypic heterogeneity and correlation to intergenic haplotype within high HbF beta-thalassemia intermedia.
abstract: OBJECTIVE
  A molecular study was carried out of beta-thalassemia intermedia patients, compound heterozygotes for mutations usually found in beta-thalassemia major, with high levels of HbF in the absence of hereditary persistence of fetal hemoglobin (HPFH) syndrome. Our objective was to locate cis-DNA structures, DNA haplotypes, motifs, or polymorphisms that may correlate with the presence of high HbF.
  
  
  METHODS
  Allele-specific oligonucleotide (ASO) hybridization was used for the detection of mutations and restriction fragment length polymorphism (RFLP) analysis and automated sequencing for motifs, haplotypes, and polymorphisms. Southern blot was used for investigating alpha-thalassemia and/or alpha- or gamma-globin genes triplications. RNA extracted from burst forming unit-erythroid (BFU-e) colonies of peripheral blood mononuclear cell cultures was used in reverse transcriptase-polymerase chain reaction (RT-PCR) to investigate intergenic transcription.
  
  
  RESULTS
  We established that (i) the combination: T haplotype of the Agamma-delta-globin intergenic region, the motif (TA)9N10(TA)10 in the HS2 site of locus control region (LCR), and TAG pre-Ggamma haplotype is sufficient but not necessary for high HbF, (ii) the genetic determinant(s) for high HbF involves an element associated with this combination and must be present in the specific R haplotype occurring in beta-thalassemia intermedia and (iii) the genetic determinant(s) for high HbF does not involve the abolition of intergenic transcription in the Agamma-delta-globin intergenic region.
  
  
  CONCLUSIONS
  The genetic determinant(s) of high HbF in the absence of HPFH is linked to intergenic haplotype T and does not disrupt intergenic transcription.
authors.affiliation: Department of General Biology, Medical Faculty, University of Patras, Athens, Greece.
authors.forename: Adamantia
authors.initials: A
authors.lastname: Papachatzopoulou
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kourakli
authors.forename: Panagiota
authors.initials: P
authors.lastname: Makropoulou
authors.forename: Theodora
authors.initials: T
authors.lastname: Kakagianne
authors.forename: Argyro
authors.initials: A
authors.lastname: Sgourou
authors.forename: Manousos
authors.initials: M
authors.lastname: Papadakis
authors.forename: Aglaia
authors.initials: A
authors.lastname: Athanassiadou
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D021901:DNA, Intergenic / Q000235:genetics*; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis* / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics*; D005914:Globins / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D040641:Quantitative Trait Loci / Q000235:genetics; D017085:alpha-Thalassemia / Q000097:blood / Q000235:genetics; D017086:beta-Thalassemia / Q000097:blood* / Q000235:genetics*
chemical_list: D021901:DNA, Intergenic; D005914:Globins; D005319:Fetal Hemoglobin