GTS5:Lynch Syndrome (MLH1, PMS2, MSH2, MSH6)

(General Instructions – The focus of these pages is the clinically significant genetic alterations in each disease type, which is based on current knowledge within the WHO classification books and using resources such as PubMed for the latest information. If the same disease is described in multiple WHO classification books, the genetics-related information for that disease will be consolidated into a single main page that has this template (other pages would only contain a link to this main page). Use HUGO-approved gene names and symbols (italicized when appropriate), HGVS-based nomenclature for variants, as well as generic names of drugs and testing platforms or assays if applicable. Please complete tables whenever possible and do not delete them (add N/A if not applicable in the table and delete the examples); to add (or move) a row or column in a table, click nearby within the table and select the > symbol that appears to be given options. Please do not delete or alter the section headings. The use of bullet points alongside short blocks of text rather than only large paragraphs is encouraged. Additional instructions below in italicized blue text should not be included in the final page content. Please also see Author_Instructions and FAQs as well as contact your Associate Editor or Technical Support)

Primary Author(s)*

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WHO Classification of Disease

(Instructions: This table’s content will be autogenerated.)

Structure	Disease
Book
Category
Family
Type
Subtype(s)

Definition / Description of Disease

Put your text here (Instructions: Include a brief general clinical description, diagnostic criteria, and differential diagnosis if applicable. Include disease context relative to other WHO classification categories, i.e. describe any organ-specific information pertinent to the genetic aspects of the disease across all applicable WHO classification books.)

Synonyms / Terminology

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Epidemiology / Prevalence

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Genetic Abnormalities: Germline

Put your text here and fill in the table (Instruction: Can include references in the table. Do not delete table. If multiple causes of the syndrome, include relative prevalence of genetic contributions to that syndrome. In the notes, include additional details about most common mutations including founder mutations, mechanisms of molecular pathogenesis, alteration-specific prognosis and any other important genetic-related information with key references.)

Gene	Genetic Variant or Variant Type	Molecular Pathogenesis	Inheritance, Penetrance, Expressivity	Notes
EXAMPLE: BRCA1	EXAMPLE: Many	EXAMPLE: Multiple variant types leading to loss of function
EXAMPLE: Gene X	EXAMPLE: List the specific mutation

Genetic Abnormalities: Somatic

Put your text here and fill in the table (Instruction: Describe significant second hit mutations, or somatic variants that present as a germline syndrome. Can include references in the table. Do not delete table. In the notes, include details about most common mutations, mechanisms of molecular pathogenesis, alteration-specific prognosis and any other important genetic-related information with key references.)

Gene	Genetic Variant or Variant Type	Molecular Pathogenesis	Inheritance, Penetrance, Expressivity	Notes
EXAMPLE: BRCA	EXAMPLE: Biallelic inactivation variants	EXAMPLE: Second hit mutation can occur as copy neutral LOH, inactivating mutation, deletion, promoter hypermethylation, or a structural abnormality disrupting the gene.
EXAMPLE: BRCA	EXAMPLE: Gain	EXAMPLE:After exposure to certain therapies (e.g. PARP inhibitors), a second mutation may restore gene function as a resistance mechanism.

Genes and Main Pathways Involved

Put your text here and fill in the table (Instructions: Can include references in the table. Do not delete table.)

Gene; Genetic Alteration	Pathway	Pathophysiologic Outcome
EXAMPLE: BRAF and MAP2K1; Activating mutations	EXAMPLE: MAPK signaling	EXAMPLE: Increased cell growth and proliferation
EXAMPLE: CDKN2A; Inactivating mutations	EXAMPLE: Cell cycle regulation	EXAMPLE: Unregulated cell division
EXAMPLE: KMT2C and ARID1A; Inactivating mutations	EXAMPLE: Histone modification, chromatin remodeling	EXAMPLE: Abnormal gene expression program

Genetic Diagnostic Testing Methods

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Additional Information

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Links

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References

(use the "Cite" icon at the top of the page) (Instructions: Add each reference into the text above by clicking where you want to insert the reference, selecting the “Cite” icon at the top of the page, and using the “Automatic” tab option to search by PMID to select the reference to insert. If a PMID is not available, such as for a book, please use the “Cite” icon, select “Manual” and then “Basic Form”, and include the entire reference. To insert the same reference again later in the page, select the “Cite” icon and “Re-use” to find the reference; DO NOT insert the same reference twice using the “Automatic” tab as it will be treated as two separate references. The reference list in this section will be automatically generated and sorted.)

Notes

*Primary authors will typically be those that initially create and complete the content of a page.  If a subsequent user modifies the content and feels the effort put forth is of high enough significance to warrant listing in the authorship section, please contact the Associate Editor or other CCGA representative.  When pages have a major update by a new author, the new author will be acknowledged at the beginning of the page, and those who contributed previously will be acknowledged below as a prior author.  Additional global feedback or concerns are also welcome.

Prior Author(s):