title: [Contribution of genetic typing for the diagnosis of familial adenomatous polyposis in pediatrics].
abstract: BACKGROUND
  The gene responsible for familial adenomatous polyposis, (APC), has been recently cloned and genetic map with several polymorphic markers has been established.
  
  
  METHODS
  Blood samples (20 ml) were taken from 34 subjects belonging to four families at risk for familial adenomatous polyposis. Nineteen of these 34, less than 20 years old, had one parent having polyposis or dead because of it. Polyposis was diagnosed, in ten of these 19 by endoscopy. Genomic DNA was extracted from peripheral leukocytes and Southern blot analyses were performed in each family, using RFLPs on both sides of the APC locus.
  
  
  RESULTS
  DNA analysis identified normal and mutant haplotypes at the APC locus in each family. It was thus possible to follow the segregation of mutant alleles. These results were compared with the anamnestic and endoscopic data. Bearing in mind the risk of recombination when using extragenic markers, RFLPs allowed early diagnosis of APC in pre and/or asymptomatic patients.
  
  
  CONCLUSIONS
  Genetic analysis can be used to diagnose APC in affected families, provided the risk of recombination is taken into account. Intragenic microsatellites markers will soon be available. These will provide more information on the APC gene, and hence direct molecular diagnosis of APC.
authors.affiliation: Service de gastroentérologie pédiatrique, hôpital Robert-Debré, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Munck
authors.forename: S
authors.initials: S
authors.lastname: Olschwang
authors.forename: B
authors.initials: B
authors.lastname: Thuille
authors.forename: J F
authors.initials: JF
authors.lastname: Mougenot
authors.forename: J P
authors.initials: JP
authors.lastname: Cézard
authors.forename: L
authors.initials: L
authors.lastname: Ferkdadji
authors.forename: C
authors.initials: C
authors.lastname: Faure
authors.forename: J
authors.initials: J
authors.lastname: Navarro
authors.forename: G
authors.initials: G
authors.lastname: Thomas
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000175:diagnosis* / Q000235:genetics*; D000293:Adolescent; D002648:Child; D002874:Chromosome Mapping; D005260:Female; D005817:Genetic Counseling; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D008297:Male
chemical_list: D005819:Genetic Markers
vernacular_title: Apport du typage génétique pour le diagnostic de polypose adénomateuse familiale en pédiatrie.