title: Molecular background of D-negative phenotype in the Tunisian population.
abstract: BACKGROUND
  Most studies of the molecular basis of Rhesus D-negative phenotype have been conducted in Caucasian and African populations. A comprehensive survey of RHD alleles was lacking in people from North Africa (Tunisians, Moroccans and Algerians) which could be very efficient for managing donors and patients carrying an RHD molecular variant. We analyse the molecular background of D-negative population in Tunisia in the present study.
  
  
  METHODS
  Blood samples were collected from native Tunisians. A total of 448 D-negative donors from different regions of Tunisia were analysed by RHD genotyping according to an adopted strategy using real-time PCR, ASP-PCR and sequencing.
  
  
  RESULTS
  Among the 448 D-negative samples, 443 were phenotyped unequivocally as true D-negative including three molecular backgrounds which were RHD gene deletion (n = 437), RHDψ pseudogene (n = 2) and RHD-CE-D hybrid gene (n = 4) with the respective frequencies of 0·9900, 0·0023 and 0·0046. The remaining five samples, in discordance with the serological results, were identified as two weak D type 11, one weak D type 29, one weak D type 4·0 and one DBT-1 partial D.
  
  
  CONCLUSIONS
  This study showed that the Tunisian population gets closer to Caucasians, given that the RHD gene deletion is the most prevalent cause of D-negative phenotype, but it is slightly different by the presence of the RHDψ pseudogene which was found with a very low frequency compared with that described in the African population. Nevertheless, the relative occurrence of weak D variants among studied serologically D-negative samples make necessary the adaptation of RHD genotyping strategy to the spectrum of prevalent alleles.
authors.affiliation: Unité de Recherche UR06SP05 Centre Régional de Transfusion Sanguine, Sousse, Tunisia.
authors.forename: H
authors.initials: H
authors.lastname: Moussa
authors.forename: M
authors.initials: M
authors.lastname: Tsochandaridis
authors.forename: T
authors.initials: T
authors.lastname: Chakroun
authors.forename: S
authors.initials: S
authors.lastname: Jridi
authors.forename: B
authors.initials: B
authors.lastname: Abdelneji
authors.forename: S
authors.initials: S
authors.lastname: Hmida
authors.forename: M
authors.initials: M
authors.lastname: Silvy
authors.forename: P
authors.initials: P
authors.lastname: Bailly
authors.forename: J
authors.initials: J
authors.lastname: Gabert
authors.forename: A
authors.initials: A
authors.lastname: Levy-Mozziconacci
authors.forename: Saloua
authors.initials: S
authors.lastname: Jemni-Yacoub
mesh_terms: D000483:Alleles; D001788:Blood Grouping and Crossmatching; D004247:DNA / Q000235:genetics; D005091:Exons / Q000235:genetics; D017353:Gene Deletion; D005786:Gene Expression Regulation / Q000235:genetics; D005787:Gene Frequency; D005838:Genotype; D006239:Haplotypes / Q000235:genetics; D006801:Humans; D010641:Phenotype; D011544:Pseudogenes; D060888:Real-Time Polymerase Chain Reaction; D012204:Rh-Hr Blood-Group System / Q000096:biosynthesis / Q000235:genetics*; D014416:Tunisia
chemical_list: D012204:Rh-Hr Blood-Group System; C026410:Rho(D) antigen; D004247:DNA