title: XmnI polymorphism is associated with fetal hemoglobin levels in hypoplastic syndromes.
abstract: OBJECTIVE
  Acquired fetal hemoglobin (HbF) elevation has been implicated as a prognostic factor in dyserythropoietic disorders. Our objectives were to examine acquired HbF increases in aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH) patients, and to evaluate whether there is an association between the presence of XmnI and 5' hypersensitive site locus control region (LCR-HS2) polymorphisms and the HbF levels.
  
  
  METHODS
  Cross-sectional study at the Hematology and Blood Transfusion Service of Universidade Federal de São Paulo - Escola Paulista de Medicina.
  
  
  METHODS
  We studied a group of 37 patients with AA and/or PNH. Polymerase chain reaction (PCR) and enzymatic digestion were utilized to analyze XmnI polymorphisms; and PCR, cloning and automated sequencing for the HS2 polymorphisms.
  
  
  RESULTS
  The mean HbF level was 2.32%, but there was no significant difference in HbF level between the AA and PNH groups (p = 0.46). HbF levels of less than 1.0% showed a significant correlation with absence of the XmnI (+) polymorphism (p = 0.02). The presence of the XmnI allele was greater in the AA group (p = 0.007).
  
  
  CONCLUSIONS
  XmnI polymorphism absence reduction is associated with acquired HbF elevation. Further studies are required to confirm these observations and make treatment, prognosis and survival comparisons.
authors.affiliation: Hematology and Blood Transfusion Service, Universidade Federal de São Paulo-Escola Paulista de Medicina, São Paulo, Brazil.
authors.forename: Marily Maria Azevedo
authors.initials: MM
authors.lastname: Shimmoto
authors.forename: Perla
authors.initials: P
authors.lastname: Vicari
authors.forename: Andréa Cristina
authors.initials: AC
authors.lastname: Fernandes
authors.forename: Gustavo Stuani
authors.initials: GS
authors.lastname: Guimarães
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Figueiredo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000741:Anemia, Aplastic / Q000097:blood / Q000235:genetics*; D003430:Cross-Sectional Studies; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics*; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis*; D006457:Hemoglobinuria, Paroxysmal / Q000097:blood / Q000235:genetics*; D006801:Humans; D019901:Locus Control Region; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic / Q000235:genetics*
chemical_list: D005319:Fetal Hemoglobin; C028649:endodeoxyribonuclease XmnI; D015252:Deoxyribonucleases, Type II Site-Specific