title: Genetic similarity of chromosome 6 between patients receiving hematopoietic stem cell transplantation and HLA matched sibling donors.
abstract: BACKGROUND
  Matching for HLA genes located on chromosome 6 is required in hematopoietic stem cell transplantation to reduce the incidence of graft-versus-host disease. However, a considerable proportion of patients still suffer from it, obviously due to genetic differences outside the HLA gene region.
  
  
  METHODS
  We studied the similarity of almost 4,000 single nucleotide polymorphisms on chromosome 6 between patients receiving hematopoietic stem cell transplantation and their HLA-matched sibling donors.
  
  
  RESULTS
  We observed that as a result of routine HLA matching the siblings in fact shared surprisingly long chromosomal fragments with similar single nucleotide polymorphism genotypes--from 11.65 Mb to 134.66 Mb. The number of genes mapped on these shared fragments varied from 402 to 1,302. Considering the whole chromosome 6, the HLA-matched siblings were apparently identical for 65.2-97.8% of the single nucleotide polymorphisms.
  
  
  CONCLUSIONS
  Potentially, genes similar in some transplantation pairs while different in others might have a significant role in determining the outcome after hematopoietic stem cell transplantation.
authors.affiliation: Finnish Red Cross Blood Service, Kivihaantie 7, 00310 Helsinki, Finland. hannu.turpeinen@veripalvelu.fi
authors.forename: Hannu
authors.initials: H
authors.lastname: Turpeinen
authors.forename: Liisa
authors.initials: L
authors.lastname: Volin
authors.forename: Lauri
authors.initials: L
authors.lastname: Nikkinen
authors.forename: Pauli
authors.initials: P
authors.lastname: Ojala
authors.forename: Aarno
authors.initials: A
authors.lastname: Palotie
authors.forename: Janna
authors.initials: J
authors.lastname: Saarela
authors.forename: Jukka
authors.initials: J
authors.lastname: Partanen
mesh_terms: D002896:Chromosomes, Human, Pair 6 / Q000235:genetics*; D006680:HLA Antigens / Q000235:genetics; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006648:Histocompatibility / Q000235:genetics*; D006650:Histocompatibility Testing / Q000379:methods; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D035781:Siblings; D014019:Tissue Donors
chemical_list: D006680:HLA Antigens