title: Xmn1-G γ polymorphism and clinical predictors of severity of disease in β-thalassemia intermedia.
abstract: BACKGROUND
  To determine the prevalence of Xmn1-(G)γ polymorphism in North Indian children and adolescents with β thalassemia intermedia (TI) and to correlate it with disease severity.
  
  
  METHODS
  All patients of thalassemia intermedia presenting to the pediatric hematology clinic of a tertiary care hospital in North India were enrolled. Clinical severity of their disease was assessed by a phenotypic score proposed by Phadke and Agarwal. They were classified according to status of their Xmn1-(G)γ polymorphism as Xmn1-(G)γ +/+, Xmn1-(G)γ +/-, and Xmn1-(G)γ -/- by molecular analysis.
  
  
  RESULTS
  A total of 104 patients were enrolled. Severe TI was seen in 56.7% (59) patients, while 43.3% (45) had non-severe TI. Jaundice was more frequent in severe TI than in non-severe TI. Xmn1-(G)γ +/+ was present in 25.9% (25) patients. The frequency of the Xmn1-(G)γ +/- and Xmn1-(G)γ -/- was 22% and 37.3% in severe TI children. The corresponding frequencies were 31.1% and 42.2% in non-severe TI group respectively. No significant correlation was observed between the Xmn1-(G)γ polymorphism and severity of thalassemia, age at onset of symptoms, age at diagnosis, age at first transfusion, transfusion frequency or average hemoglobin levels. HbF level was significantly higher in Xmn1-(G)γ +/+ and Xmn1-(G)γ +/- patients.
  
  
  CONCLUSIONS
  This study showed that although the prevalence of Xmn1-(G)γ polymorphism is high in β thalassemia intermedia patients, it alone could not predict clinical severity in TI patients. Further refinement and validation of clinical scoring system is necessary for guiding appropriate management.
authors.affiliation: Department of Pediatrics, Pediatric Hematology-Oncology Unit, Advanced Pediatric Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, UT, India.
authors.forename: Sapna
authors.initials: S
authors.lastname: Oberoi
authors.forename: Reena
authors.initials: R
authors.lastname: Das
authors.forename: Inusha
authors.initials: I
authors.lastname: Panigrahi
authors.forename: Jasbir
authors.initials: J
authors.lastname: Kaur
authors.forename: Ram K
authors.initials: RK
authors.lastname: Marwaha
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism*; D005260:Female; D006454:Hemoglobins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007194:India; D007223:Infant; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D017086:beta-Thalassemia / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology*
chemical_list: D006454:Hemoglobins; C028649:endodeoxyribonuclease XmnI; D015252:Deoxyribonucleases, Type II Site-Specific