title: APC, MYH, and the correlation genotype-phenotype in colorectal polyposis.
abstract: BACKGROUND
  Familial adenomatous polyposis (FAP) has been divided into two entities: classical (CFAP) and attenuated (AFAP). With the discovery of MYH associated polyposis (MAP) syndrome, the clinical differences have become unclear. The aim of our study was to investigate patients with polyposis treated in our institution for a correlation between genotype and phenotype.
  
  
  METHODS
  Between 1978 and 2007, 515 patients were followed. Four groups were identified: AFAP, CFAP, MAP, and no-mutation patients. Clinical, surgical, histological, and genetic data of patients were collected and compared. Two ranges of mutations responsible for AFAP were used.
  
  
  RESULTS
  Patient breakdown was CFAP patients (n = 322/294), AFAP patients (n = 13/41), MYH patients (n = 17) and no-mut patients (n = 32). Patients not tested for APC mutation (n = 131) were excluded. Genotype/phenotype evaluation showed no difference in the number or location of polyps, age at colectomy, presence of cancer, or duodenal polyps. Major differences were found for MYH patients: later age at diagnosis, more cancers, fewer polyps, and more located in the right part of the colon. For phenotype/genotype correlation, patients aged more than 35 years at the time of colectomy and with fewer than 100 polyps had significantly more mutation found on MYH.
  
  
  CONCLUSIONS
  This two-way analysis did not show any correlation that might help to identify a subgroup of patients with APC mutation that may be considered attenuated. It is more likely that the MAP syndrome is the real AFAP.
authors.affiliation: Department of Digestive Surgery, Hopital Saint-Antoine, University Paris VII Pierre & Marie Curie, Paris, France. jeremie.lefevre@sat.aphp.fr
authors.forename: Jérémie H
authors.initials: JH
authors.lastname: Lefevre
authors.forename: Yann
authors.initials: Y
authors.lastname: Parc
authors.forename: Magali
authors.initials: M
authors.lastname: Svrcek
authors.forename: Solen
authors.initials: S
authors.lastname: Kernéis
authors.forename: Chrystelle
authors.initials: C
authors.lastname: Colas
authors.forename: Conor
authors.initials: C
authors.lastname: Shields
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Flejou
authors.forename: Rolland
authors.initials: R
authors.lastname: Parc
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Tiret
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D045647:DNA Glycosylases / Q000235:genetics*; D005260:Female; D017491:Genes, APC; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010641:Phenotype; D013577:Syndrome; D055815:Young Adult
chemical_list: D045647:DNA Glycosylases; C061738:mutY adenine glycosylase