OBJECTIVETo gain an insight into large genomic deletions in mismatch repair genes MSH2 and MLH1 in Chinese hereditary nonpolyposis colorectal cancer (HNPCC) patients in order to improve genetic detections of HNPCC kindreds.

METHODSFourteen peripheral blood DNA samples were obtained from 14 unrelated HNPCC patients, and fluorescent labeled quantitative multiplex PCR was used to detect large genomic deletions in MSH2 and MLH1 genes.

RESULTSOne of the fourteen probands, a man, was found to have MSH2 exon 1-7 deletions. His cancer-distressed son was also found to have the mutations. Additionally, three normal members of the family had the same mutations.

CONCLUSIONLarge genomic deletions which mainly present to MSH2 account for 20% of general pathological sequence changes of MSH2 and MLH1 genes in Chinese HNPCC patients, and large genomic detections of mismatch repair genes should be included in the regular genetic detections of Chinese HNPCC kindreds.