title: Novel RHD alleles with weak hemagglutination and genetic Exon 9 diversity: weak D Types 45.1, 75, and 76.
abstract: BACKGROUND
  Molecular variant RHD allele analysis is best complemented by detailed characterization of the associated D phenotype.
  
  
  METHODS
  Variant D types were characterized using molecular typing, RHD sequencing, extended serologic D antigen investigations, and flow cytometric D antigen quantification.
  
  
  RESULTS
  We discovered three novel weak D types termed weak D Types 45.1, 75, and 76 with RHD nucleotide substitutions coding for amino acid exchanges in predicted intracellular RhD polypeptide stretches; antigen densities of approximately 1.990, 900, and 240 D sites per red blood cell were found, respectively. Adsorption-elution technique-supported D epitope mapping of these three weak D types demonstrated the expression of all tested D epitopes. Initial molecular typing of the three investigated samples by RHD gene exon scanning polymerase chain reaction using sequence-specific priming yielded a negative reaction for A1193 located in RHD Exon 9 and could be explained by specific mutations for weak D Types 45.1 (C818T, G1195A), 75 (G1194C), and 76 (A1215C).
  
  
  CONCLUSIONS
  All novel weak D types expressed all tested D epitopes. It is of interest that for weak D Types 45.1, 75, and 76, similar alleles with a maximal divergence of one amino acid only, that is, weak D Types 45, 41, and 68, respectively, have been reported so far.
authors.affiliation: Blood Transfusion Service Zurich, Swiss Red Cross, Zurich, Switzerland; Central Institute for Blood Transfusion and Immunological Department, General Hospital and University Clinics Innsbruck, Innsbruck, Austria; Department of Obstetrics and Gynecology, Medical University Innsbruck, Innsbruck, Austria; Urology, Medical University Innsbruck, Innsbruck, Austria; inno-Train Diagnostik GmbH, Kronberg i.T., Germany; Labor Wisplinghoff, Cologne, Germany; Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Gassner
authors.forename: Irene
authors.initials: I
authors.lastname: Utz
authors.forename: Harald
authors.initials: H
authors.lastname: Schennach
authors.forename: Angela
authors.initials: A
authors.lastname: Ramoni
authors.forename: Hannes
authors.initials: H
authors.lastname: Steiner
authors.forename: Sabine
authors.initials: S
authors.lastname: Scholz
authors.forename: Ursula
authors.initials: U
authors.lastname: Kreklau
authors.forename: Günther F
authors.initials: GF
authors.lastname: Körmöczi
mesh_terms: D000483:Alleles; D001782:Blood Donors; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D004912:Erythrocytes / Q000276:immunology / Q000378:metabolism; D005091:Exons / Q000235:genetics*; D018628:Gene Dosage; D014644:Genetic Variation; D006384:Hemagglutination / Q000235:genetics; D006386:Hemagglutination Tests; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012204:Rh-Hr Blood-Group System / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D012698:Serologic Tests
chemical_list: D000939:Epitopes; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen