title: Three uncommon KEL alleles in one family with unusual Kell phenotypes explain a 35-year old conundrum.
abstract: BACKGROUND
  Kell is a complex blood group system comprising 35 antigens. Kell antigens are absent from rare red cells of the Ko (null) phenotype and expressed only weakly in the Kmod phenotype. Molecular analysis of three uncommon KEL alleles elucidated the obscure pattern of inheritance of Kell antigens in one family.
  
  
  METHODS
  Standard serological methods were employed. All exons, flanking intronic sequence and introns 15 and 16 of KEL were sequenced from genomic DNA. cDNA was obtained from erythroid cells cultured from progenitor cells isolated from peripheral blood.
  
  
  RESULTS
  The Kmod propositus was heterozygous for two KEL mutations: c.2107G>A, p.Gly703Arg and a synonymous mutation, c.1719C>T, in the codon for p.573Gly. Sequencing of cDNA revealed that c.1719C>T caused skipping of exon 16, resulting in a silent allele. Her KEL:3,-4 brother was heterozygous for KEL*03/04 and c.1719C/T.
  
  
  CONCLUSIONS
  A synonymous mutation caused complete exon skipping, despite being located 16 bases downstream of the 3′ splice site, resulting in a null KEL allele. The combined effects of two mod alleles, one responsible for KEL3 expression and the other for p.Gly703Arg, were probably responsible for an unexpected KEL:3,-4 phenotype.
authors.forename: V
authors.initials: V
authors.lastname: Karamatic Crew
authors.forename: J
authors.initials: J
authors.lastname: Poole
authors.forename: N
authors.initials: N
authors.lastname: Burton
authors.forename: G
authors.initials: G
authors.lastname: Daniels
mesh_terms: D000483:Alleles; D019943:Amino Acid Substitution / Q000235:genetics*; D001120:Arginine / Q000235:genetics; D001483:Base Sequence; D002478:Cells, Cultured; D004912:Erythrocytes / Q000276:immunology; D015672:Erythroid Precursor Cells / Q000276:immunology; D005260:Female; D017353:Gene Deletion; D006580:Genetic Carrier Screening; D005998:Glycine / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D007626:Kell Blood-Group System / Q000097:blood / Q000235:genetics* / Q000276:immunology*; D008297:Male; D009154:Mutation; D010375:Pedigree; D022821:RNA Splice Sites / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D007626:Kell Blood-Group System; D022821:RNA Splice Sites; D001120:Arginine; D005998:Glycine