MLPA And DHPLC Technology Platform Based Pathogenic APC Gene Mutation Screening Of Familial Adenomatous Polyposis Predigrees And Analysis Of Mutation Molecular Mechanism

Objective: This study screened familial adenomatous polyposis（FAP） pedigrees pathogenic adenomatous polyposis coli（APC）gene germline mutations to find novel mutations and/or find the APC gene germline mutation characteristics of Chinese FAP patients, at the same time to detect multiplex ligationdependent probe amplification（MLPA） and denaturing High Performance Liquid Chromatography（DHPLC） technology platform based gene diagnosis effect.Methods: Extraction 14 FAP pedigree members peripheral blood DNA which were treated in our hospital since 2005 to 2013, and combined application of MLPA, PCR-DHPLC and direct sequencing were used to look for FAP pedigrees pathogenic APC gene germ line mutations, soon afterwards, the base sequence around the mutation points were analyzed to explore the characteristics of germline mutations in the APC gene.Results: We fund 6 micromutations out of 14 FAP pedigrees, while there were no large duplications and/or deletions fund. These germline mutations are c.5432C>T（p.Ser1811Leu）, two c.3926₃930del AAAAG（p.Glu1309 Aspfs X4）, c.3921₃924del AAAA（p.Ile1307 Metfs X13）, c.3184₃187del CAAA（p.Gln1061 Aspfs X59） and c.4127₄126del AT（p.Tyr1376 Lysfs X9）, respectively, and all deletion mutations resulted in a premature stop codon. At the same time, we fund c.3921₃924del AAAA and two c.3926₃930del AAAAG are located in AAAAG short tandem repeats, c.3184₃187del CAAA is located in the CAAA interrupted direct repeats, and c.4127₄128 del AT is located in the 5’-CCTGAACA-3’,3’-ACAAGTCC-5 palindromes（inverted repeats） of the APC gene, furthermore, deletion mutations are mostly located at condon 1 309.Conclusions: Even there were no novel mutations fund as the pathogenic gene of FAP in this study, but we fund nucleotide sequence containing short tandem repeats and palindromes（inverted repeats） are mutations in high incidence area in APC gene, which is dominated by small deletion mutations, especially the 5 bp base deletion at codon 1 309, at the same time we fund MLPA and DHPLC technology platform based gene diagnosis is quickly and efficiently.