Abstract for presentation at 11th International Congress of Human Genetics

Analysis of common alpha-thalassemia point mutations and deletions by reverse-hybridization

  • Helene Puehringer, ViennaLab Labordiagnostika GmbH, Vienna, Austria
  • Hossein Najmabadi, Genetics Research Center, University of Social Welfare & Rehabilitation Sciences, Tehran, Iran
  • Hai-Yang Law, Genetics Service, KK Women's and Children's Hospital, Singapore
  • Walter Krugluger, Department of Clinical Chemistry, Rudolfstiftung Hospital, Vienna, Austria
  • Vip Viprakasit, Dept. Paediatrics, Siriraj Hospital, Mahidol University, Bangkok, Thailand
  • Serge Pissard, Lab de Genetique et de Biochimie, Hopital Henri Mondor, Creteil, France
  • Amein Al-Ali, Department of Clinical Biochemistry, College of Medicine, King Faisal University, Dammam, Saudi Arabia
  • Christian Oberkanins, ViennaLab Labordiagnostika GmbH, Vienna, Austria

    • Alpha-thalassemia (alpha-thal) is observed in high frequencies throughout Southeast Asia, India, the Middle East, parts of Africa and the Mediterranean area. It is characterized by the reduced synthesis or absence of alpha-globin chains due to mutations affecting one or both genes. The clinical phenotype varies from asymptomatic to lethal (Hb Bart’s hydrops fetalis) according to the number of impaired alpha-globin genes.
    We have developed a reverse-hybridization assay (Alpha-Globin StripAssay) for the rapid and simultaneous detection of 21 alpha-globin mutations: two single gene deletions (-3.7; -4.2), five double gene deletions (MED; SEA; THAI; FIL; –20.5 kb), anti-3.7 gene triplication, two point mutations in the alpha 1 gene (cd 14: TGG-TAG; cd 59: Hb Adana GGC>GAC) and eleven point mutations in the alpha 2 gene (init cd: ATG>ACG; cd 19: -G; IVS1: 5nt del; cd 59: GGC>GAC; cd 125: Hb Quong Sze CTG>CCG; cd 142: Hb Constant Spring TAA>CAA; cd 142: Hb Icaria TAA>AAA, cd 142: Hb Pakse TAA>TAT; cd 142: Hb Koya Dora TAA>TCA; poly A-1: AATAAA-AATAAG; poly A-2: AATAAA-AATGAA). The test is based on multiplex DNA amplification (including gap-PCR) and hybridization to teststrips presenting a parallel array of allele-specific oligonucleotide probes for each variant. The entire procedure from blood sampling to the identification of mutations requires less than 6 hours, and hybridization/detection may be carried out manually or essentially automated using existing instrumentation (e.g. TECAN profiBlot). The Alpha-Globin StripAssay has been carefully validated, both on pre-typed reference samples, as well as in routine diagnostic settings.

    Conference Organiser - ICMS Pty Ltd