title: RHD zygosity assignments based on most probable genotype and hybrid Rhesus box detection in Tunisia.
abstract: BACKGROUND
  Determination of the RHD zygosity is important for genetic counselling and risk evaluation of hemolytic disease of the newborn HDN in women with D iso-immunisation.
  
  
  OBJECTIVE
  We proposed to determine the genotype frequencies of the RHD locus using a PCR-SSP method and assignment of the most probable genotype (MPG) and analyse the concordance between the two methods.
  
  
  METHODS
  The complete Rh phenotype and the frequencies of RH haplotypes were determined on 506 blood donors. RHD zygosity was determined by both assignment of the MPG and PCR-SSP specific for the hybrid Rhesus box. For RH:-1 samples, analysis of the RHD exon 10 was done to detect eventual RHD aberrant alleles.
  
  
  RESULTS
  Among the 466 RH:1 samples, 54.08% were hemizygous and 45.92% homozygous by PCR-SSP, and 64.16% hemizygous and 35.84% homozygous by the MPG. The comparison between the methods showed discordant results in 135 RH:1 samples. For the 40 RH:-1 samples, hybrid Rhesus box was detected in all samples and RHD exon 10 was detected in three samples suggesting unequivocal alleles identified as one RHDψ, one (C)ce(s) and one weak D type 4.
  
  
  CONCLUSIONS
  The PCR-SSP should replace the MPG. However, studying of aberrant RHD alleles and aberrant Rhesus boxes could confirm the accuracy of this method in Tunisian population.
authors: Centre Régional de Transfusion Sanguine, Unité de recherche UR06SP05, Sousse, Tunisia.
authors: Narjes
authors: N
authors: Kacem
authors: Tahar
authors: T
authors: Chakroun
authors: Hajer
authors: H
authors: Moussa
authors: Saïda
authors: S
authors: Abdelkefi
authors: Betoul
authors: B
authors: Houissa
authors: Jacques
authors: J
authors: Chiaroni
authors: Saloua
authors: S
authors: Jemni Yacoub
mesh_terms: D000328:Adult; D000483:Alleles; D004899:Erythroblastosis, Fetal / Q000235:genetics*; D005260:Female; D056426:Genetic Loci; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods*; D012203:Rh Isoimmunization / Q000235:genetics*; D012204:Rh-Hr Blood-Group System / Q000235:genetics*; D014416:Tunisia
chemical_list: D012204:Rh-Hr Blood-Group System