Fig. 2.

Pathogenic mosaic variants in tissue DNA, but not in leukocyte DNA from patients 13 and 14. a Patient 13, HRM: an aberrant curve from polyp DNA in amplicon 15.14 in repeated experiments. b Patient 13, direct sequencing: forward sequence from DNA samples isolated from three different polyps showing a c.4057G>T variant with an allelic fraction estimated at ~20–50 % in the sequence trace. This variant was not detectable in blood by sequencing (b) and HRM (data not shown). c Patient 14, HRM: an aberrant curve in overlapping amplicons 15.19 and 15.20 in repeated experiments, from DNA samples isolated from two different polyps, with different histology, adenomatous and hyperplastic. d Patient 14, direct sequencing: forward sequence showing a c.4666dup variant in both polyps, with an estimated allelic fraction of ~30 %. This variant was not detectable in blood, by sequencing (d) and HRM (data not shown) [Color figure can be viewed in the online issue, which is available at http://link.springer.com/]