title: A de novo germline MLH1 mutation in a Lynch syndrome patient with discordant immunohistochemical and molecular biology test results.
abstract: We describe a patient with a Homo sapiens mutL homolog 1 (MLH1)-associated Lynch syndrome with previous diagnoses of two distinct primary cancers: a sigmoid colon cancer at the age of 39 years, and a right colon cancer at the age of 50 years. The mutation identified in his blood and buccal cells, c.1771delG, p.Asp591Ilefs*25, appears to be a de novo event, as it was not transmitted by either of his parents. This type of de novo event is rare in MLH1 as only three cases have been reported in the literature so far. Furthermore, the discordant results observed between replication error phenotyping and immunohistochemistry highlight the importance of the systematic use of both pre-screening tests in the molecular diagnosis of Lynch syndrome.
authors.affiliation: CHU Nantes, Service de Génétique Médicale, 9 quai Moncousu, Nantes Cedex 1, France. fabrice.airaud@chu-nantes.fr
authors.forename: Fabrice
authors.initials: F
authors.lastname: Airaud
authors.forename: Sébastien
authors.initials: S
authors.lastname: Küry
authors.forename: Isabelle
authors.initials: I
authors.lastname: Valo
authors.forename: Ingrid
authors.initials: I
authors.lastname: Maury
authors.forename: Dominique
authors.initials: D
authors.lastname: Bonneau
authors.forename: Olivier
authors.initials: O
authors.lastname: Ingster
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bezieau
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000328:Adult; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D005260:Female; D018095:Germ-Line Mutation; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics*; D010375:Pedigree
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1
keywords: De novo mutation; Homo sapiens mutL homolog 1; Immunohistochemistry; Lynch syndrome; Replication error phenotype