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World J Gastroenterol. Oct 21, 2012; 18(39): 5635-5639
Published online Oct 21, 2012. doi: 10.3748/wjg.v18.i39.5635
Published online Oct 21, 2012. doi: 10.3748/wjg.v18.i39.5635
A de novo germline MLH1 mutation in a Lynch syndrome patient with discordant immunohistochemical and molecular biology test results
Fabrice Airaud, Sébastien Küry, Ingrid Maury, Stéphane Bezieau, CHU Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes Cedex 1, France
Isabelle Valo, Institut de Cancérologie de l’Ouest, Service d’Anatomie et Cytologie Pathologique, 2 rue Moll, 49933 Angers Cedex 9, France
Dominique Bonneau, Olivier Ingster, CHU Angers, Service de Génétique Médicale, 4 rue Larrey, 49933 Angers, France
Author contributions: Airaud F, Küry S and Bezieau S designed research and wrote the paper; Valo I performed the anatomopathology research; Maury I performed the molecular biology research; and Bonneau D and Ingster O performed the clinical investigation.
Correspondence to: Fabrice Airaud, MSc, CHU Nantes, Service de Génétique Médicale, 9 quai Moncousu, 44093 Nantes Cedex 1, France. fabrice.airaud@chu-nantes.fr
Telephone: +33-240-084299 Fax: +33-240-084026
Received: April 4, 2012
Revised: June 14, 2012
Accepted: July 18, 2012
Published online: October 21, 2012
Revised: June 14, 2012
Accepted: July 18, 2012
Published online: October 21, 2012
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.
Keywords: Lynch syndrome, Homo sapiens mutL homolog 1, De novo mutation, Replication error phenotype, Immunohistochemistry