Mismatch repair gene mutation spectrum in the Swedish Lynch syndrome population

Research output: Contribution to journalArticle

Abstract

Lynch syndrome caused by constitutional mismatch-repair defects is one of the most common hereditary cancer syndromes with a high risk for colorectal, endometrial, ovarian and urothelial cancer. Lynch syndrome is caused by mutations in the mismatch repair (MMR) genes i.e., MLH1, MSH2, MSH6 and PMS2. After 20 years of genetic counseling and genetic testing for Lynch syndrome, we have compiled the mutation spectrum in Sweden with the aim to provide a population-based perspective on the contribution from the different MMR genes, the various types of mutations and the influence from founder mutations. Mutation data were collected on a national basis from all laboratories involved in genetic testing. Mutation analyses were performed using mainly Sanger sequencing and multiplex ligation-dependent probe amplification. A total of 201 unique disease-predisposing MMR gene mutations were identified in 369 Lynch syndrome families. These mutations affected MLH1 in 40%, MSH2 in 36%, MSH6 in 18% and PMS2 in 6% of the families. A large variety of mutations were identified with splice site mutations being the most common mutation type in MLH1 and frameshift mutations predominating in MSH2 and MSH6. Large deletions of one or several exons accounted for 21% of the mutations in MLH1 and MSH2 and 22% in PMS2, but were rare (4%) in MSH6. In 66% of the Lynch syndrome families the variants identified were private and the effect from founder mutations was limited and predominantly related to a Finnish founder mutation that accounted for 15% of the families with mutations in MLH1. In conclusion, the Swedish Lynch syndrome mutation spectrum is diverse with private MMR gene mutations in two-thirds of the families, has a significant contribution from internationally recognized mutations and a limited effect from founder mutations.

Details

Authors
  • Kristina Lagerstedt-Robinson
  • Anna Rohlin
  • Christos Aravidis
  • Beatrice Melin
  • Margareta Nordling
  • Marie Stenmark-Askmalm
  • Annika Lindblom
  • Mef Nilbert
Organisations
External organisations
  • Karolinska Institutet
  • University of Gothenburg
  • Sahlgrenska University Hospital
  • Uppsala University
  • Umeå University
  • Linköping University
  • Skåne University Hospital
  • University of Copenhagen
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cancer and Oncology

Keywords

  • EPCAM, Hereditary colorectal cancer, HNPCC, Lynch syndrome, MLH1, MSH2, MSH6
Original languageEnglish
Pages (from-to)2823-2835
Number of pages13
JournalOncology Reports
Volume36
Issue number5
Publication statusPublished - 2016 Nov 1
Publication categoryResearch
Peer-reviewedYes

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