Low mutation rate of hMSH2 and hMLH1 in Taiwanese hereditary non-polyposis colorectal cancer
Journal
Clinical Genetics
Journal Volume
64
Journal Issue
3
Pages
243-251
Date Issued
2003
Author(s)
Abstract
Hereditary non-polyposis colorectal cancer (HNPCC), the most common type of hereditary colorectal cancer, is thought to be a simple Mendelian disease involving DNA mismatch repair genes. The majority of mutations associated with HNPCC occur in the hMSH2 and hMLH1 genes. The reported incidence of mismatch repair gene mutations in HNPCC kindreds varies considerably (from 22 to 86%), and most mutations are unique. This study aimed to determine the genetic basis of Taiwanese HNPCC kindreds, focusing on the two major genes involved in this disease. A total of 15 Taiwanese HNPCC kindreds meeting the Amsterdam criteria, including 72 affected individuals among a total of 266 individuals, were analyzed using both RNA- and DNA-based methods. The mutation rate of hMSH2 and hMLH1 in these 15 kindreds was 0% and 20%, respectively, which is lower than that reported in other countries. Two novel mutations were discovered in hMLH1: one was an allelic loss of a 5.2-kb genomic fragment causing exon 16 deletion; and the other was a two-nucleotide deletion that resulted in a frameshift mutation of exon 3. We also identified one hMLH1 exon 4 mutation (a C to T transition in codon 117), which had been reported previously in western countries. This is the first genetic study of HNPCC from Taiwan.
Other Subjects
cytosine; DNA; nucleotide; protein MLH1; protein MSH2; RNA; tyrosine; allele; article; codon; colorectal cancer; controlled study; exon; female; frameshift mutation; gene deletion; gene identification; gene mutation; genetic analysis; genetic association; heredity; human; human cell; incidence; major clinical study; male; mismatch repair; mutation rate; priority journal; Taiwan; Adenocarcinoma; Adult; Aged; Base Pair Mismatch; Base Sequence; Carrier Proteins; Codon; Colorectal Neoplasms, Hereditary Nonpolyposis; DNA Mutational Analysis; DNA Repair; Ethnic Groups; Exons; Female; Genotype; Humans; Male; Middle Aged; Molecular Sequence Data; Neoplasm Proteins; Neoplasms; Nuclear Proteins; Reverse Transcriptase Polymerase Chain Reaction; Sequence Analysis, DNA; Sequence Deletion; Taiwan
Type
journal article