title: Comprehensive analysis of RHD splicing transcripts reveals the molecular basis for the weak anti-D reactivity of Del -red blood cells.
abstract: BACKGROUND
  Of the Rh blood type, Del is a rare variant that elicits the weakest anti-D reactivity. In this study, we revisit the genetic changes of Del allele and characterise the RHD splicing transcripts to realise the molecular basis of Del formation in the Taiwanese population.
  
  
  METHODS
  The RHD exons from Del and D-positive individuals were amplified by polymerase chain reaction (PCR) using different primer pairs followed by sequencing analyses. In addition, full-length RHD transcripts were reversed transcribed and amplified by nested-PCR. The type and frequency of the RHD splicing transcripts were analysed after sequencing the PCR products that were subcloned into a cloning vector.
  
  
  RESULTS
  All Del individuals had a characteristic 1227G>A mutation. No deletion of the exon sequences was found. At least nine types of RHD splicing transcripts including exons 7/8/9 deletion, 7/9 deletion, 8/9 deletion, 9 deletion, 2/3/7/9 deletion, 2/3/7/8/9 deletion, exons 7/8/9 deletion with replacement of exon 3 with RHCE exon 3, exon 9 deletion with cryptic insertion of 170 bp of intron 7 and exons 7/8/9 deletion with cryptic insertion of 117 bp of intron 3 were identified in the Del -RBC. These aberrant splicing transcripts led to production of frame shift or truncated D antigen. Notably, no full-length RHD transcript was identified in the Del -RBC.
  
  
  CONCLUSIONS
  The RHD 1227G>A mutation contributes to the molecular basis of Del phenotype in the Taiwanese population. The point mutation results in aberrant frame shift or exon deletion transcripts and generates D protein with weak antigen presenting function.
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital.|Department of Medical Biotechnology and Laboratory Science, College of Medicine.
authors.forename: D-P
authors.initials: DP
authors.lastname: Chen
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital.|Department of Pathology, School of Medicine.
authors.forename: C-F
authors.initials: CF
authors.lastname: Sun
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital.|Department of Medical Biotechnology and Laboratory Science, College of Medicine.
authors.forename: H-C
authors.initials: HC
authors.lastname: Ning
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital.
authors.forename: W-T
authors.initials: WT
authors.lastname: Wang
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital.|Department of Medical Biotechnology and Laboratory Science, College of Medicine.|Molecular Medicine Research Center, Chang Gung University, Taoyuan County, Taiwan.
authors.forename: C-P
authors.initials: CP
authors.lastname: Tseng
mesh_terms: D005091:Exons; D005260:Female; D006801:Humans; D054643:INDEL Mutation; D008297:Male; D017354:Point Mutation; D012326:RNA Splicing; D012204:Rh-Hr Blood-Group System / Q000235:genetics* / Q000276:immunology; D013624:Taiwan
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen
keywords: Del; adsorption-elution; exon deletion; point mutation; splicing error