Major contribution from recurrent alterations and MSH6 mutations in the Danish Lynch syndrome population.
An increasing number of mismatch-repair (MMR) gene mutations have been identified in hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome. This study presents the population-based Danish MMR gene mutation profile, which contains 138 different MMR gene alterations. Among these, 88 mutations in 164 families are considered pathogenic and an additional 50 variants from 76 families are considered to represent variants of unknown pathogenicity. The different MMR genes contribute to 40% (MSH2), 29% (MLH1), and 22% (MSH6) of the mutations and the Danish population thus shows a considerably higher frequency of MSH6 mutations than previously described. Although 69/88 (78%) pathogenic mutations were present in a single family, previously recognized recurrent/founder mutations were causative in 75/137 (55%) MLH1/MSH2 mutant families. In addition, the Danish MLH1 founder mutation c.1667+2_1667_+8TAAATCAdelinsATTT was identified in 14/58 (24%) MLH1 mutant families. The Danish Lynch syndrome population thus demonstrates that MSH6 mutations and recurrent/founder mutations have a larger contribution than previously recognized, which implies that the MSH6 gene should be included in routine diagnostics and suggests that directed analysis of recurrent/founder mutations may be feasible e.g. in families were diagnostic material is restricted to archival tissue.
Nilbert
Mef
M
Clinical Research Centre and HNPCC-Register, Copenhagen University, Hvidovre University Hospital, Kettegård Allé 30, Hvidovre, 2650, Denmark. Mef.Nilbert@med.lu.se
Wikman
Friedrik P
FP
Hansen
Thomas V O
TV
Krarup
Henrik B
HB
Orntoft
Torben F
TF
Nielsen
Finn C
FC
Sunde
Lone
L
Gerdes
Anne-Marie
AM
Cruger
Dorthe
D
Timshel
Susanne
S
Bisgaard
Marie-Louise
ML
Bernstein
Inge
I
Okkels
Henrik
H
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics*; D003718:Denmark; D005260:Female; D018703:Founder Effect; D006801:Humans; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein / Q000235:genetics; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C094443:G-T mismatch-binding protein; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein