XmnI polymorphism is associated with fetal hemoglobin levels in hypoplastic syndromes.
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.
Shimmoto
Marily Maria Azevedo
MM
Hematology and Blood Transfusion Service, Universidade Federal de São Paulo-Escola Paulista de Medicina, São Paulo, Brazil.
Vicari
Perla
P
Fernandes
Andréa Cristina
AC
Guimarães
Gustavo Stuani
GS
Figueiredo
Maria Stella
MS
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*
D005319:Fetal Hemoglobin; C028649:endodeoxyribonuclease XmnI; D015252:Deoxyribonucleases, Type II Site-Specific