title: Safe fetal platelet genotyping: new developments.
abstract: BACKGROUND
  Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is due to maternal alloimmunization against fetal platelet (PLT) antigens. Antenatal management strategies have been developed to avoid complications such as intracranial hemorrhage. The aim of this study was to set up two reliable, noninvasive fetal genotyping assays to determine the fetal risk in pregnancies in which the father is heterozygous for the offending antigen. This study focused on human PLT antigen (HPA)-1, the most frequently implicated antigen in FNAIT in Caucasians.
  
  
  METHODS
  Two assays based on cell-free fetal DNA extracted from maternal blood samples and on real-time polymerase chain reaction (QPCR) were developed: an allele-specific QPCR specifically targeting the polymorphic sequence in HPA-1 and the study of the variation in the high-resolution melting curve of amplicons containing the polymorphic region.
  
  
  RESULTS
  All results from the 49 samples obtained from 29 pregnant women were consistent with expectations. Six women were compatible with their fetuses (three HPA-1aa women and three HPA-1bb women), 41 HPA-1bb women were incompatible with their fetuses, as were two HPA-1aa women.
  
  
  CONCLUSIONS
  Two fetal PLT genotyping assays on maternal blood samples proved to be reliable as of 15 weeks of gestation, thereby avoiding invasive techniques such as amniocentesis.
authors.affiliation: Platelet Immunology Laboratory, INTS, Paris, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Le Toriellec
authors.forename: Christophe
authors.initials: C
authors.lastname: Chenet
authors.forename: Cecile
authors.initials: C
authors.lastname: Kaplan
mesh_terms: D000328:Adult; D016824:Antigens, Human Platelet / Q000235:genetics*; D015331:Cohort Studies; D005260:Female; D005819:Genetic Markers; D005820:Genetic Testing / Q000379:methods*; D060005:Genotyping Techniques; D006801:Humans; D007231:Infant, Newborn; D039661:Integrin beta3; D008297:Male; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D060888:Real-Time Polymerase Chain Reaction; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000175:diagnosis* / Q000235:genetics
chemical_list: D016824:Antigens, Human Platelet; D005819:Genetic Markers; C061248:ITGB3 protein, human; D039661:Integrin beta3; C083451:human platelet antigen 1b