Presymptomatic diagnosis using a deletion of a single codon in families with hereditary non-polyposis colorectal cancer

TY - JOUR

T1 - Presymptomatic diagnosis using a deletion of a single codon in families with hereditary non-polyposis colorectal cancer

AU - Ripa, Rasmus Sejersten

AU - Katballe, Niels

AU - Wikman, Friedrik

AU - Jäger, Anne Charlotte

AU - Bernstein, Inge

AU - Orntoft, Torben

AU - Schwartz, Marianne

AU - Nielsen, Finn Cilius

AU - Bisgaard, Marie Luise

PY - 2005/2/15

Y1 - 2005/2/15

N2 - The diagnosis of hereditary non-polyposis colorectal cancer (HNPCC) is often confirmed by a mutation in one of several mismatch-repair genes, in particular MLH1, MSH2 and MSH6. Presymptomatic diagnosis requires the identification of a mutation causing the disease. Three different deletions of a single amino acid codon have previously been published as assumed pathogenic. The objective of this study was to determine if an MSH2 3 base pair in-frame deletion (N596del) could be used in presymptomatic screening of at-risk individuals. We report on five HNPCC families with the N596del mutation, identified after mutation screening of MSH2 and MLH1. All patients in the families were haplotyped using markers flanking the MSH2 gene. The haplotypes revealed that the five families with high probability descended from only two founders. The N596del segregated with the HNPCC phenotype with lod scores of 3.2 and 2.0 at the recombination fraction of 0.0 in the two founder families. Sequencing of MSH2 and MLH1 did not reveal other pathogenic mutations, and N596del was not identified in 50 healthy controls. The mutation has previously been found expressed in mRNA, and is located in a conserved domain. The results support the hypothesis that N596del is the disease causing mutation and not a clinically silent variation. On this basis, the application of the MSH2 N596del mutation, in presymptomatic screening of HNPCC families, is recommended.

AB - The diagnosis of hereditary non-polyposis colorectal cancer (HNPCC) is often confirmed by a mutation in one of several mismatch-repair genes, in particular MLH1, MSH2 and MSH6. Presymptomatic diagnosis requires the identification of a mutation causing the disease. Three different deletions of a single amino acid codon have previously been published as assumed pathogenic. The objective of this study was to determine if an MSH2 3 base pair in-frame deletion (N596del) could be used in presymptomatic screening of at-risk individuals. We report on five HNPCC families with the N596del mutation, identified after mutation screening of MSH2 and MLH1. All patients in the families were haplotyped using markers flanking the MSH2 gene. The haplotypes revealed that the five families with high probability descended from only two founders. The N596del segregated with the HNPCC phenotype with lod scores of 3.2 and 2.0 at the recombination fraction of 0.0 in the two founder families. Sequencing of MSH2 and MLH1 did not reveal other pathogenic mutations, and N596del was not identified in 50 healthy controls. The mutation has previously been found expressed in mRNA, and is located in a conserved domain. The results support the hypothesis that N596del is the disease causing mutation and not a clinically silent variation. On this basis, the application of the MSH2 N596del mutation, in presymptomatic screening of HNPCC families, is recommended.

KW - Adult

KW - Base Sequence

KW - Codon

KW - Colorectal Neoplasms, Hereditary Nonpolyposis

KW - DNA

KW - DNA-Binding Proteins

KW - Female

KW - Haplotypes

KW - Humans

KW - Male

KW - Middle Aged

KW - Molecular Sequence Data

KW - MutS Homolog 2 Protein

KW - Mutation

KW - Pedigree

KW - Proto-Oncogene Proteins

KW - Sequence Deletion

U2 - 10.1016/j.mrfmmm.2004.10.002

DO - 10.1016/j.mrfmmm.2004.10.002

M3 - Journal article

C2 - 15680406

SN - 0027-5107

VL - 570

SP - 89

EP - 96

JO - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis

JF - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis

IS - 1

ER -