title: Molecular and hematological characteristics of a novel form of α-globin gene triplication: the hemoglobin St.Luke's-Thailand [α95(G2)Pro→Arg] or Hb St. Luke's [A2] HBA2.
abstract: OBJECTIVE
  This study aims to report a hitherto un-described α-globin gene triplicated allele with a novel hemoglobin (Hb) variant on α2-globin gene, Hb St.Luke's-Thailand [α95(G2)Pro-Arg].
  
  
  METHODS
  A study was done on a 1.5-year-old Thai boy who showed pallor and jaundice after birth. Hb analysis was performed by HPLC and capillary electrophoresis. cDNAs of the two α-globin genes were analyzed by sequencing and novel diagnostic methods based on PCR-RFLP and multiplex PCR assays were developed.
  
  
  RESULTS
  Hb analysis by both HPLC and capillary electrophoresis revealed unknown variants for Hb A (amounting to 9.0 and 9.4%) and Hb A2 (0.7 and 0.6%). cDNA analysis of α-globin genes revealed a normal α1-globin gene sequence and a CCG (Pro) to CGG (Arg) mutation at codon 95 of the α2-globin gene leading to the Hb St.Luke's-Thailand or Hb St. Luke's [A2] HBA2: c.287C>G. DNA analysis of the patient and his mother identified the in cis α-globin gene triplication. This novel orientation of α-globin gene could be confirmed by PCR-NlaIV restriction digestion or a multiplex allele specific PCR assay developed.
  
  
  CONCLUSIONS
  A relatively lower percentage of the Hb St.Luke's-Thailand due to a HBA2 gene mutation could be explained by a linked anti-3.7 α-globin gene triplication. Clinical and hematological features, effect of α-globin gene triplication on the phenotypic expression of Hb St.Luke's-Thailand and diagnostics using combined HPLC, capillary electrophoresis and molecular techniques were presented.
authors: The Graduate School, Khon Kaen University, Khon Kaen, Thailand.
authors: Kritsada
authors: K
authors: Singha
authors: Goonnapa
authors: G
authors: Fucharoen
authors: Arunee
authors: A
authors: Jetsrisuparb
authors: Supan
authors: S
authors: Fucharoen
mesh_terms: D001483:Base Sequence; D005260:Female; D020440:Gene Duplication; D006441:Hemoglobin A / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D055815:Young Adult; D055542:alpha-Globins / Q000235:genetics*
chemical_list: D006455:Hemoglobins, Abnormal; D055542:alpha-Globins; C039485:hemoglobin St. Luke's; D006441:Hemoglobin A