title: RHD alleles among pregnant women with serologic discrepant weak D phenotypes from a multiethnic population and risk of alloimmunization.
abstract: BACKGROUND
  A considerable number of RHD alleles responsible for weak and partial D phenotypes have been identified. Serologic determination of these phenotypes is often doubtful and makes genetic analysis of RHD gene highly desirable in transfusion recipients and pregnant women. We analyzed the RHD gene in a cohort of pregnant women with doubtful D phenotypes.
  
  
  METHODS
  RHD genotyping was performed on 104 cases with D typing discrepancies or with history of serologic weak D phenotype. Laboratory-developed DNA tests, RHD BeadChip (Bioarray Solutions, Immucor), and sequencing were used to identify the RHD alleles.
  
  
  RESULTS
  Molecular analyses showed 23 of 104 (22%) pregnant women were RHD*weak D types 1, 2, or 3 and not at risk for anti-D. Fifty-one (49%) were RHD*weak partial 4.0, 6 RHD*weak D type 38 (6%), 1 RHD*weak D type 45 (1%), 1 RHD*weak D type 67 (1%), and potentially at risk for being alloimmunized and making anti-D. Partial D was identified in 22 of 104 (21%) patients and definitively at risk for anti-D.
  
  
  CONCLUSIONS
  Appropriate classification of RhD phenotypes is recommended for correct indication of RhIG in pregnant women. However, the serologic distinction between RhD-negative and RhD-positive phenotypes is a difficult task in the case of D variants due to the variations in serologic testing. Our results show a great variability in RHD variant alleles in pregnant women from this population of high admixture. According to these results, 78% of these obstetric patients are at risk for anti-D and candidates for RhIG.
authors.affiliation: Hemotherapy and Cellular Therapy Department, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
authors.forename: Carolina Bonet
authors.identifier: http://orcid.org/0000-0001-5103-4970
authors.initials: CB
authors.lastname: Bub
authors.affiliation: Hemotherapy and Cellular Therapy Department, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
authors.forename: Maria Giselda
authors.initials: MG
authors.lastname: Aravechia
authors.affiliation: Hemotherapy and Cellular Therapy Department, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
authors.forename: Thiago Henrique
authors.initials: TH
authors.lastname: Costa
authors.affiliation: Hemotherapy and Cellular Therapy Department, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
authors.forename: José Mauro
authors.initials: JM
authors.lastname: Kutner
authors.affiliation: Hemotherapy and Cellular Therapy Department, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.|Hemocentro Unicamp, Campinas, Brazil.
authors.forename: Lilian
authors.initials: L
authors.lastname: Castilho
mesh_terms: D001788:Blood Grouping and Crossmatching; D015331:Cohort Studies; D005260:Female; D005838:Genotype; D060005:Genotyping Techniques / Q000379:methods*; D006801:Humans; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012203:Rh Isoimmunization / Q000276:immunology / Q000517:prevention & control; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology*; D018029:Rho(D) Immune Globulin / Q000276:immunology
chemical_list: C061961:RHO(D) antibody; D012204:Rh-Hr Blood-Group System; D018029:Rho(D) Immune Globulin; C026410:Rho(D) antigen
keywords: D variants; RHD alleles; genetic counseling; partial D; pregnant women; weak D