title: Problems in determining thalassemia carrier status in a program for prevention and control of severe thalassemia syndromes: a lesson from Thailand.
abstract: BACKGROUND
  Prevention and control of severe β thalassemia by carrier detection and identification of couples at risk in developed countries is one of the most successful stories in modern medicine. Similar programs in developing countries especially Southeast Asia, are more problematic because both α and β thalassemias are highly prevalent. In Thailand, there are limited data on whether we could determine, based on hematological phenotypes, the mutation severity and/or coinheritance of α thalassemia in β thalassemia traits.
  
  
  METHODS
  Comprehensive molecular, hematology and hemoglobin analyses of the α and β globin genes were performed in 141 healthy individuals identified as β thalassemia carriers.
  
  
  RESULTS
  Seventeen different β globin mutations were successfully identified out of all cases analyzed. Although the majority of the mutations identified were the β⁰ or severe β⁺ thalassemia alleles, a high proportion of mild mutations (25%) was observed. Of these β thalassemia traits, 22.3% were found to co-inherit the α thalassemias. Milder hematological phenotypes were noted in β⁺ compared with β⁰ thalassemia traits when the α globin genes were intact. Although co-inheritance of α⁰ thalassemia might be suspected in cases with skewed profiles, due to the overlapping values, it remains difficult to apply these parameters for reliable carrier determination.
  
  
  CONCLUSIONS
  A combination of hemoglobin analysis and DNA testing seems to be the best way to confirm carrier status in a region with high frequency for both α and β thalassemias. Underdiagnoses of carrier status could hamper the effectiveness of a thalassemia prevention and control program.
authors.affiliation: Faculty of Medicine, Department of Pediatrics and Thalassemia Center, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. vip.vip@mahidol.ac.th
authors.forename: Vip
authors.initials: V
authors.lastname: Viprakasit
authors.forename: Chanin
authors.initials: C
authors.lastname: Limwongse
authors.forename: Sathein
authors.initials: S
authors.lastname: Sukpanichnant
authors.forename: Pornpimol
authors.initials: P
authors.lastname: Ruangvutilert
authors.forename: Chompunut
authors.initials: C
authors.lastname: Kanjanakorn
authors.forename: Waraporn
authors.initials: W
authors.lastname: Glomglao
authors.forename: Monchan
authors.initials: M
authors.lastname: Sirikong
authors.forename: Witayakarn
authors.initials: W
authors.lastname: Utto
authors.forename: Voravarn S
authors.initials: VS
authors.lastname: Tanphaichitr
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D009154:Mutation; D017422:Sequence Analysis, DNA; D013577:Syndrome; D013785:Thailand; D055815:Young Adult; D017085:alpha-Thalassemia / Q000097:blood* / Q000235:genetics / Q000517:prevention & control*; D055544:beta-Globins / Q000235:genetics; D017086:beta-Thalassemia / Q000097:blood* / Q000235:genetics / Q000517:prevention & control*
chemical_list: D055544:beta-Globins