title: Human platelet antigen polymorphisms (HPA-1, -2, -3, -4, -5 and -15) in major ethnic groups of Pakistan.
abstract: OBJECTIVE
  Gene frequencies of human platelet antigens (HPA) determine the magnitude of platelet immunological disorders like neonatal alloimmune thrombocytopenia, platelet refractoriness and ease of availability of particular HPA-typed platelet donors in a given community.
  
  
  BACKGROUND
  However, the pattern of HPA in Pakistani population is not known.
  
  
  OBJECTIVE
  The aim of present study was to determine the gene frequencies of HPA (HPA-1 to -5 and -15) in individuals belonging to major ethnic groups and castes of Pakistani population.
  
  
  METHODS
  HPA genotyping was done in 593 individuals belonging to all ethnic groups of Pakistan, by polymerase chain reaction-sequence specific primers with detection on polyacrylamide electrophoresis.
  
  
  RESULTS
  The gene frequencies of the 'a' and 'b' alleles of HPA-1 to -5 and -15 in Pakistanis were as follows: HPA-1a/b, 0.885/0.115; HPA-2a/b, 0.92/0.08; HPA-3a/b, 0.69/0.31; HPA-4a/b, 1/0; HPA-5a/b, 0.9/0.1; HPA-15a/b, 0.59/0.41. Except for significant difference regarding gene frequency of HPA-3 between Pathans and Sindhis, there was no significant difference of HPA-1 to -5 and -15 between major ethnic groups of Pakistan. The estimated mismatch probability regarding platelet antigens 1-5 and 15 in Pakistanis, after transfusion of random donor platelets, is from 14 to 37%. The expected incidence of neonatal alloimmune thrombocytopenia due to anti-HPA-1a in Pakistani pregnant females is < 1 of 1000 pregnancies and 8-12 of 1000 in case of anti-HPA-5b. Homozygosity of HPA-1b, -2b and -5b genotypes ranged from 1 to 2% in the Pakistani population, whereas homozygosity of HPA-3b and -15b was 11 and 18%.
  
  
  CONCLUSIONS
  There is a need to establish donor registries typed for HPA in the transfusion centres of the country.
authors: PNS Shifa Hospital, Karachi, Pakistan. farhatab@hotmail.com
authors: F A
authors: FA
authors: Bhatti
authors: M
authors: M
authors: Uddin
authors: A
authors: A
authors: Ahmed
authors: P
authors: P
authors: Bugert
mesh_terms: D015703:Antigens, CD / Q000235:genetics*; D016824:Antigens, Human Platelet / Q000235:genetics*; D001771:Blood Banks; D001788:Blood Grouping and Crossmatching; D003430:Cross-Sectional Studies; D005006:Ethnicity / Q000235:genetics*; D005260:Female; D058851:GPI-Linked Proteins; D005787:Gene Frequency; D005838:Genotype; D006301:Health Services Needs and Demand; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D008297:Male; D009363:Neoplasm Proteins / Q000235:genetics*; D010154:Pakistan / Q000453:epidemiology; D010980:Platelet Membrane Glycoproteins / Q000235:genetics*; D011247:Pregnancy; D012042:Registries; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000208:ethnology / Q000235:genetics
chemical_list: D015703:Antigens, CD; D016824:Antigens, Human Platelet; C120523:CD109 protein, human; D058851:GPI-Linked Proteins; D009363:Neoplasm Proteins; D010980:Platelet Membrane Glycoproteins