title: A novel complex mutation in MSH2 contributes to both Muir-Torre and Lynch Syndrome.
abstract: Mutations in mismatch repair genes lead to Lynch Syndrome, the most common form of inherited colorectal cancer. In this report, we describe a novel complex germline mutation c.[1601_1661+92dup; 1591_1611del] of the mismatch repair gene, MSH2. This mutation, which segregates with the disease phenotype, was discovered in a Lynch syndrome kindred that also shows a history of the Muir-Torre syndrome. Interestingly, several tumors from this family displayed microsatellite instability, a hallmark of Lynch syndrome tumors but no consistent, concomitant loss of MSH2 protein expression. In addition, a subset of tumors showed neither prototypical feature of microsatellite instability nor immunohistochemistry deficiency, highlighting the importance of a detailed molecular analysis of rare genetic alterations. This mutation and the atypical clinical manifestations observed underscore the genetic complexity underlying Lynch syndrome, and the importance of comprehensive molecular screening in the diagnosis and early detection of colorectal and other associated cancers.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sheron
authors.initials: S
authors.lastname: Perera
authors.forename: Lily
authors.initials: L
authors.lastname: Ramyar
authors.forename: Angie
authors.initials: A
authors.lastname: Mitri
authors.forename: Aaron
authors.initials: A
authors.lastname: Pollett
authors.forename: Steven
authors.initials: S
authors.lastname: Gallinger
authors.forename: Marsha D
authors.initials: MD
authors.lastname: Speevak
authors.forename: Melyssa
authors.initials: M
authors.lastname: Aronson
authors.forename: Bharati
authors.initials: B
authors.lastname: Bapat
mesh_terms: D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics* / Q000503:physiopathology; D019295:Computational Biology; D053843:DNA Mismatch Repair; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D018095:Germ-Line Mutation; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D053842:Microsatellite Instability; D055653:Muir-Torre Syndrome / Q000235:genetics* / Q000503:physiopathology; D051718:MutS Homolog 2 Protein / Q000235:genetics*; D010375:Pedigree
chemical_list: D051718:MutS Homolog 2 Protein