[Detection mutations in the DNA mismatch repair genes of hMLH1 and hMSH2 genes in Colombian families with suspicion of hereditary non-polyposis colorectal carcinoma (Lynch syndrome)].
BACKGROUND
Colorectal cancer (CRC) is the second highest cause of cancer mortality in developed countries. In Colombia, CRC ranks fifth as a cause of cancer death. Approximately 75% of CRC appear to be spontaneous and 25% are familial, with 5% of the latter clearly hereditary. Of these, hereditary non-polyposis colorectal carcinoma (HNPCC)-or Lynch syndrome is the most important.


OBJECTIVE
Herein, the two most important genes involved in Lynch syndrome, the hMLH1 and hMSH2 were analyzed for presence of mutations.


METHODS
Seventeen Colombian families that fulfilled the Amsterdam II criteria or Bethesda guidelines for Lynch syndrome were selected. The of 35 exons of hMLH1 and hMSH2 genes were screened by SSCP and those with electrophoretic variants were sequenced.


RESULTS
Eight germinal mutations were detected, corresponding to a 47% detection mutation rate. Six of the eight mutations have previously been reported. These consisted of the following mutations: a single base substitution at the donor splicing site of exon 9, a single base substitution (A>G) at codon 755 of the exon 17, and another single base substitution (G>A) at codon 681 of exon 18. The two novel mutations consisted of a single base substitution (C>T) at codon 640 of exon 17 of the hMLH1 gene and a two-nucleotide deletion (TG) at codon 184 of exon 3 of hMSH2 gene. In addition, two families were observed with a polymorphism in the intron 13 (G>A) nt 1558+14, of hMLH1 gene.


CONCLUSIONS
This study represented the first survey for detecting mutations associated with Lynch syndrome in Colombia, and is intended to lead to the establishment of a management and prevention program.
Gómez
Andrea
A
Facultad de Medicina e Instituto de Genética, Universidad Nacional de Colombia, Bogotá, D. C., Colombia.
Salguero
Gustavo
G
García
Herbert
H
Aristizábal
Fabio
F
Gutiérrez
Oscar
O
Angel
Luis Alberto
LA
Padrón
Jorge
J
Martínez
Carlos
C
Martínez
Humberto
H
Malaver
Omar
O
Barvo
Rosa
R
Giraldo
Alejandro
A
D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D000328:Adult; D020137:Base Pair Mismatch; D002352:Carrier Proteins / Q000235:genetics*; D003105:Colombia; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis / Q000235:genetics*; D004252:DNA Mutational Analysis; D004260:DNA Repair; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein