title: [A Family Affected by Lynch Syndrome Caused by MSH6 Germline Mutation].
abstract: The clinical features of Lynch syndrome caused by MSH6 are not fully understood since very few cases have been described in Japan. We report 2 cases of Lynch syndrome with germline mutation of MSH6 in a family. Case 1: A 47-year-old man was referred to our department due to positive fecal occult blood test. He had family history of endometrial cancer and gastric cancer (mother), and bladder cancer (father). We performed sigmoidectomy for sigmoid cancer. The pathological findings revealed mucosal cancer (pTis, pN0, H0, P0, pStage 0). Since the patient met the revised Bethesda guidelines, we performed microsatellite instability (MSI) testing and immunohistochemistry for mismatch repair genes (MLH1, MSH2, MSH6, and PMS2) as screening for Lynch syndrome. MSI-high and loss of MSH6 were found. Based on these results, genetic testing of MSH6 revealed a frame-shift mutation in codon 604 (c. 1806-1809delAAG/p. Glu604LeufsX5). Case 2: The patient was a younger brother of case 1. The same mutation was detected in the MSH6 gene.
authors.affiliation: Dept. of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University.
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Chika
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kumamoto
authors.forename: Okihide
authors.initials: O
authors.lastname: Suzuki
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukuchi
authors.forename: Takeaki
authors.initials: T
authors.lastname: Matsuzawa
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kumagai
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Ishibashi
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Eguchi
authors.forename: Erito
authors.initials: E
authors.lastname: Mochiki
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ishida
mesh_terms: D001483:Base Sequence; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000150:complications / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D018095:Germ-Line Mutation; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D010375:Pedigree; D012811:Sigmoid Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery
chemical_list: D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein