Non-sense mediated mRNA decay causes differential allelic expression in CHEK2*1100delC carriers. Allelic ratio measurements were performed on genomic DNA (gDNA), cDNA derived from LCLs in standard cell culture condition, and cDNA from LCLs treated with puromycin, an NMD inhibiting agent. (A) For a carrier of the mutation, comparison of gDNA and cDNA melting profiles supports the existence of DAE. Puromycin-cDNA profile resembles gDNA, supporting the role of NMD in the DAE observed in this individual. (B) The wild-type sample shows similar profiles in all three situations. HRM profiles were generated with the R script.