title: Information recovery in cancer families: value for risk estimations.
abstract: BACKGROUND
  Drawing an informative pedigree is fundamental in genetic counselling. It is very common for some parts of pedigrees to remain ambiguous because of the proband's inability to recall the past history of her/his family. Current age, date of birth, date of death and age of diagnosis are the commonest missing information in pedigrees.
  
  
  METHODS
  The Scottish Social Statistics website, National Statistics website and English language literature were used to model extrapolations. About 172 Grampian families and three high-risk Grampian families with complete information were chosen to evaluate the influence of extrapolations on models' performance. Differences between original data and extrapolated data were assessed by independent samples t-test.
  
  
  RESULTS
  Changes made by extrapolations in age- and cancer-related information were not statistically significant (P > 0.05) in comparison with original data, except for average age of diagnosis of breast cancer (P = 0.03). The differences made by extrapolations in estimated probabilities generated by probability assessment models were small and ignorable except that for Tyrer-Cuzick model for Grampian family 3.
  
  
  CONCLUSIONS
  Extrapolations based on National Health Statistics can scientifically cover missing information in a defined population with minimum effect on performance of probability assessment models.
authors.affiliation: Department of Medicine & Therapeutics, College of Life Sciences & Medicine, Polwarth Building, Foresterhill, Aberdeen, UK. h.roudgari@abdn.ac.uk
authors.forename: Hassan
authors.initials: H
authors.lastname: Roudgari
authors.forename: Lindsey F
authors.initials: LF
authors.lastname: Masson
authors.forename: Neva E
authors.initials: NE
authors.lastname: Haites
mesh_terms: D000328:Adult; D019313:BRCA1 Protein / Q000235:genetics; D004198:Disease Susceptibility / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D009369:Neoplasms / Q000175:diagnosis* / Q000235:genetics; D010375:Pedigree; D012307:Risk Factors; D012984:Software
chemical_list: D019313:BRCA1 Protein