title: How do we identify RHD variants using a practical molecular approach?
abstract: Serologic resolution of Rh discrepancies due to partial D or weak D phenotypes is a frequent problem encountered during routine typing that can be solved by RHD genotyping because it provides better characterization of these variants. The objective of the current study was to develop algorithms for identification of D variants in multiethnic populations based on a logic sequence of molecular tests using a large number of atypical RhD specimens. Thus, a total of 360 blood samples with atypical D antigen expression were analyzed. A previously published multiplex polymerase chain reaction (PCR) procedure was performed and depending on multiplex PCR analysis, the associated RHCE allele, and D variant frequency in our population, an algorithm was developed composed of six flow charts using specific PCR-restriction fragment length polymorphism and/or specific exon sequencing. This strategy allowed the identification of 22 different variants with few assays and a much reduced cost. This study describes a simple and practical algorithm that we use to determine RHD genotypes in samples with unknown RHD. This strategy is relatively easy to implement and the algorithm can be adapted to populations with various ethnic backgrounds after an initial assessment of the type and frequency of D variants. Essentially, we demonstrate that sequencing of all RHD exons is not necessary for the identification of the majority of known D variants.
authors.affiliation: Colsan-Associação Beneficente de Coleta de Sangue, São Paulo, SP, Brazil.
authors.forename: Carine Prisco
authors.initials: CP
authors.lastname: Arnoni
authors.forename: Flavia Roche Moreira
authors.initials: FR
authors.lastname: Latini
authors.forename: Janaína Guilhem
authors.initials: JG
authors.lastname: Muniz
authors.forename: Diana
authors.initials: D
authors.lastname: Gazito
authors.forename: Rosangela de Medeiros
authors.initials: Rde M
authors.lastname: Person
authors.forename: Tatiane Aparecida
authors.initials: TA
authors.lastname: de Paula Vendrame
authors.forename: José Augusto
authors.initials: JA
authors.lastname: Barreto
authors.forename: Lilian
authors.initials: L
authors.lastname: Castilho
mesh_terms: D000465:Algorithms; D001782:Blood Donors; D001938:Brazil; D004252:DNA Mutational Analysis / Q000379:methods*; D005787:Gene Frequency; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide; D012204:Rh-Hr Blood-Group System / Q000235:genetics*
chemical_list: C066468:RHCE protein, human; D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen