Table 1 The 10 cases of mosaicism
Family PersIDDiagnosis/number of adenomasAgeColorectal carcinoma (C) and Dukes stageExtra-colonicInvestigated material*MutationMosaicism (% represents proportion of affected alleles quantified with pyroseqencing)Method of detection of mosaicismFig.
151887.1100s31NoNoL (n = 1)847C>TArg283X28%DGGE1
253124.1100s42C42FGP desmoidL (n = 2)847C>TArg283X17%DGGE1
Rectum, B1Sequence
353696.1AFAP41C40Not examinedL (n = 2)847C>TArg283X5%DGGE1
453253.130–5049C50Not examinedL (n = 4)646C>TArg216XLymphocytes 6%DGGE (adenomas and lymphocytes)3
Sigmoid, B2A (n = 3)Adenoma 1 80%Sequence (adenomas only)
Adenoma 2 80%
519014.3Numerous polyps40No5–10 duodenal polypsL (n = 3)1778G>ATrp593XLymphocytes 31%DGGE2
619015.3No symptoms71Not examinedNot examinedL (n = 2)896_897 delCTSer299fsLymphocytes 0%DGGE2
F (n = 1)Skin fibroblasts 0%Sequence (mutation only detectable in offspring)
719211.1∼10045NoGlioblastomaL (n = 1)4308 delTSer1436fsLymphocytes 0%PTT
A (n = 5)Adenoma 1 16%Sequence
Adenoma 2 21%
853538.1100s36NoDuodenal polypsL (n = 2)3927_3931 del5Ser1309fsLymphocytes 30%PTT
919229.2100s35C35Sigmoid, C2Two duodenal adenomasL (n = 3)3925_3926 delGASer1309fsLymphocytes 25%PTTSequence
1053037.13573NoNot examinedL (n = 1)3067dupAThr1023fsLymphocytes 15%PTT
  • The mutations were initially identified by DGGE (cases 1–6) or PTT (cases 7–10), characterised by direct DNA sequencing and quantified using pyrosequencing. In cases 1 and 10, only one DNA sample was available; in the other cases the mutant allele could be confirmed in independent DNA samples.

  • AFAP, attenuated familial adenomatous polyposis; C, colorectal carcinoma; DGGE, denaturing gradient gel electrophoresis; FAP, familial adenomatous polyposis; FGP, fundic gland polyposis; PTT, protein truncation test.

  • *n = number of samples. DNA isolated from: A, adenoma; F, skin fibroblasts; L, lymphocytes.