Table 1

Detailed histological findings and results of APC mutation screening in blood and polyp samples of the seven cases with mosaic APC mutations

Patient IDSample IDHistologyGrade of dysplasiaLocalisation of polypsTruncating APC mutationSequencing method (number of mutant reads/read depth=% mutant reads)
(A) Mosaic cases in polyp screening cohort (n=20)
F1243Lc.3283C>T; p.Gln1095*Exome (2/213=1%);
Multiplicom (33/1875=1.8%)
T1Tubulovillous adenomaLow gradeApproximately 50 cm ab anoExome (4/35=11%)
T2Tubulovillous adenoma, partly hyperplastic polypLow gradeApproximately 40 cm ab anoExome (11/39=28%)
F1543Lc.1495C>T;p.Arg499*Multiplicom (22/17 460=0.1%)
T1Tubular adenomaLow gradeRectumSanger
T2Tubular adenomaLow gradeCaecumSanger
T3Tubular adenomaLow gradeRectumTruSight (65/364=18%)
F1676Lc.2840_2841delGT; p.Cys947Phefs*15Exome (19/220=9%); Multiplicom (129/2149=6%)
T1Tubular adenomaLow gradeTransverse colonExome (16/55=29%)
T2Tubular adenomaLow gradeCaecumExome (45/130=35%)
T1c.4348C>T;p.Arg1450* (second hit?)Exome (6/34=18%)
F5000Lmutation not detectableExome (0/67=0%);
Multiplicom (0/2650=0%)
T1Tubular adenomaLow gradeDescending colonc.4127_4128delAT; p.Tyr1376Cysfs*9Exome (2/3=67%)
T2Tubular adenomaLow grade13 cm distal from valvula bauhiniExome (23/25=92%)
T3Tubular adenomaLow grade33 cm distal from valvula bauhiniExome (12/28=43%)
T4Tubular adenomaLow grade33 cm distal from valvula bauhiniExome (2/12=17%)
F5018Lc.1660C>T;p.Arg554*Exome (32/286=11%);
Multiplicom (97/1061=9%)
T1Tubular adenomaLow gradeSigmoid colonExome (4/16=25%)
T2Tubular adenomaLow gradeRectumExome (3/5=60%)
T2c.4348C>T;p.Arg1450* (second hit?)Exome (4/12=33%)
(B) Mosaic cases in leucocyte screening cohort (n=80)
F1252Lc.896_897delCT; p.Ser299Leufs*27Exome (7/77=9%);
Multiplicom (344/3643=9%)
T1Tubulovillous adenomaLow gradeSigmoid colonSanger
T2Tubular adenomaLow gradeApproximately 40 cm ab anoSanger
F1727Lc.2240C>G;p.Ser747*Exome (2/26=8%);
Multiplicom (113/2083=5%)
T1Tubulovillous adenomaLow gradeApproximately 23 cm ab anoSanger
T2Tubulovillous adenomaLow gradeApproximately 45 cm ab anoSanger
T3Tubulovillous adenomaLow gradeApproximately 39 cm ab anoSanger
T4Tubulovillous adenomaLow gradeApproximately 32 cm ab anoSanger
  • L, leucocyte DNA; T, adenoma DNA.