title: Delta globin gene variations leading to reduction in HbA2levels.
abstract: BACKGROUND
  Mutations in the δ-globin gene are not pathogenically relevant, but co-inheritance of δ-globin variants along with β-globin gene defects can mask the diagnosis of β-thalassaemia trait.
  
  
  METHODS
  Routine haematological parameters were carried out. Molecular analysis of β-globin gene mutations was carried out by CRDB, ARMS and DNA sequencing. δ- globin gene analysis was carried out by DNA sequencing.
  
  
  RESULTS
  In this case study, we report a β-thalassaemia trait (IVS 1-5G→C) (HBB:c.92 + 5G→C) with HbA2of 1% showing the presence of δ-globin gene variant HbA2St. George CD 81 (C→T) (HBD:c.244C→T). A similar observation was reported in another unrelated patient who showed near absence of HbA2level in HPLC. He showed a presence of δ-globin gene mutation HbA2Saurashtra CD 100(C→T) (HBD: c.301C→T) and a single 3.7 kb deletion in the α-globin gene.
  
  
  CONCLUSIONS
  In the countries, where β-thalassaemia is prevalent, an awareness and detection of different δ-globin gene mutations is important, as complex interactions between these haemoglobinopathies can lead to the misdiagnosis of β-thalassaemia carriers.
authors.affiliation: National Institute of Immunohaematology (ICMR), K.E.M. Hospital Campus, Parel, Mumbai, India.
authors.forename: P
authors.initials: P
authors.lastname: Hariharan
authors.affiliation: National Institute of Immunohaematology (ICMR), K.E.M. Hospital Campus, Parel, Mumbai, India.
authors.forename: S
authors.initials: S
authors.lastname: Colaco
authors.affiliation: National Institute of Immunohaematology (ICMR), K.E.M. Hospital Campus, Parel, Mumbai, India.
authors.forename: R
authors.initials: R
authors.lastname: Colah
authors.affiliation: Surat Raktadan Kendra and Research Center, Udhana, Surat, India.
authors.forename: K
authors.initials: K
authors.lastname: Ghosh
authors.affiliation: National Institute of Immunohaematology (ICMR), K.E.M. Hospital Campus, Parel, Mumbai, India.
authors.forename: A
authors.initials: A
authors.lastname: Nadkarni
mesh_terms: D003951:Diagnostic Errors; D006443:Hemoglobin A2 / Q000032:analysis* / Q000172:deficiency; D006453:Hemoglobinopathies / Q000175:diagnosis; D006801:Humans; D009154:Mutation; D017422:Sequence Analysis, DNA; D055544:beta-Globins / Q000235:genetics; D017086:beta-Thalassemia / Q000175:diagnosis; D055546:delta-Globins / Q000235:genetics*
chemical_list: D055544:beta-Globins; D055546:delta-Globins; D006443:Hemoglobin A2
keywords: India; low HbA2 level; β-globin gene; β-thalassaemia; δ-thalassaemia