title: β-Thalassemia mutations in subjects with borderline HbA₂ values: a pilot study in North India.
abstract: BACKGROUND
  Interpreting hemoglobin high performance liquid chromatograms with borderline HbA₂ values is often problematic, especially in antenatal cases if the partner is a known thalassemia trait.
  
  
  METHODS
  We tested for underlying β-thalassemia mutations in 25 subjects with borderline HbA₂ values (between 3.0%-4.0%). Amplification refractory mutation system (ARMS-PCR) was used to detect the five common Indian β-thalassemia mutations: (IVS-I-5 (G>C), IVS-I-1 (G>T), codons 8/9 (+G), codons 41/42 (-TTCT) and 619 bp deletion). β-Globin gene sequencing was performed if no mutation was detected.
  
  
  RESULTS
  A β-globin gene defect was identified in 8 (32%) of the 25 cases with HbA₂ levels ranging from 3.5%-3.9%. ARMS-PCR revealed IVS-I-5 (G>C) in three, 619 bp deletion in two and codons 41/42 (-TTCT) in one case. Two cases had CAP +1 (A>C) mutation on gene sequencing. IVS-I-1 (G>T) and codons 8/9 (+G) were not found in this small cohort.
  
  
  CONCLUSIONS
  Mutation analysis should be offered to all at-risk couples with borderline HbA₂, especially those with values between 3.5% and 4.0% and microcytic hypochromic indices. Significant mutations different from those in other ethnic populations were seen in this small institution-based study.
authors: Department of Hematology, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, India. rangan.aruna@gmail.com
authors: Aruna
authors: A
authors: Rangan
authors: Prashant
authors: P
authors: Sharma
authors: Tina
authors: T
authors: Dadu
authors: Renu
authors: R
authors: Saxena
authors: Ishwar C
authors: IC
authors: Verma
authors: Manorama
authors: M
authors: Bhargava
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D004252:DNA Mutational Analysis; D006443:Hemoglobin A2 / Q000032:analysis*; D006801:Humans; D007194:India; D007223:Infant; D008875:Middle Aged; D009154:Mutation; D010865:Pilot Projects; D012307:Risk Factors; D017384:Sequence Deletion; D055815:Young Adult; D017086:beta-Thalassemia / Q000175:diagnosis* / Q000235:genetics
chemical_list: D006443:Hemoglobin A2