title: β-Globin gene sequencing of hemoglobin Austin revises the historically reported electrophoretic migration pattern.
abstract: BACKGROUND
  Hemoglobin (Hb) Austin was defined in 1977, using amino acid sequencing of samples from 3 unrelated Mexican-Americans, as a substitution of serine for arginine at position 40 of the β-globin chain (Arg40Ser). Its electrophoretic migration on both cellulose acetate (pH 8.4) and citrate agar (pH 6.2) was reported between Hb F and Hb A, and this description persists in reference literature. OBJECTIVES.-To review the clinical features and redefine the diagnostic characteristics of Hb Austin.
  
  
  METHODS
  Eight samples from 6 unrelated individuals and 2 siblings, all with Hispanic surnames, were submitted for abnormal Hb identification between June 2010 and September 2011. High-performance liquid chromatography, isoelectric focusing (IEF), citrate agar electrophoresis, and bidirectional DNA sequencing of the entire β-globin gene were performed.
  
  
  RESULTS
  DNA sequencing confirmed all 8 individuals to be heterozygous for Hb Austin (Arg40Ser). Retention time on high-performance liquid chromatography and migration on citrate agar electrophoresis were consistent with that identification. Migration on IEF, however, was not between Hb F and Hb A, as predicted from the report of cellulose acetate electrophoresis. By IEF, Hb Austin migrated anodal to ("faster than") Hb A.
  
  
  CONCLUSIONS
  Hemoglobin Austin (Arg40Ser) appears on IEF as a "fast," anodally migrating, Hb variant, just as would be expected from its amino acid substitution. The cited historic report is, at best, not applicable to IEF and is probably erroneous. Our observation of 8 cases in 16 months suggests that this variant may be relatively common in some Hispanic populations, making its recognition important. Furthermore, gene sequencing is proving itself a powerful and reliable tool for definitive identification of Hb variants.
authors.affiliation: From the Department of Pathology, Parkland Health and Hospital System, Children's Medical Center, Dallas, Texas (Drs Racsa, Luu, Park, and Timmons), the Department of Pathology, University of Texas Southwestern Medical Center, Dallas (Drs Racsa, Luu, Park, and Timmons); and the Department of Pathology, Children's Medical Center, Dallas (Dr Mitui).
authors.forename: Lori D
authors.initials: LD
authors.lastname: Racsa
authors.forename: Hung S
authors.initials: HS
authors.lastname: Luu
authors.forename: Jason Y
authors.initials: JY
authors.lastname: Park
authors.forename: Midori
authors.initials: M
authors.lastname: Mitui
authors.forename: Charles F
authors.initials: CF
authors.lastname: Timmons
mesh_terms: D000293:Adolescent; D019943:Amino Acid Substitution; D001483:Base Sequence; D001797:Blood Protein Electrophoresis; D002648:Child; D002851:Chromatography, High Pressure Liquid; D004252:DNA Mutational Analysis; D004588:Electrophoresis, Cellulose Acetate; D005260:Female; D006239:Haplotypes; D006455:Hemoglobins, Abnormal / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification*; D006801:Humans; D007223:Infant; D007525:Isoelectric Focusing; D008297:Male; D017422:Sequence Analysis, DNA; D055544:beta-Globins / Q000737:chemistry / Q000235:genetics*
chemical_list: D006455:Hemoglobins, Abnormal; D055544:beta-Globins