Definition

Lynch syndrome is a cancer predisposition syndrome caused by hereditary variants in the DNA mismatch repair (MMR) genes; this panel includes MLH1, MSH2, MSH6, PMS2, and EPCAM, in addition to PMS1 and MLH3. MLH1 variants account for approximately 40% of Lynch syndrome cases. Loss of function leads to microsatellite instability; colorectal and endometrial cancer are the most common, and cancers generally appear at an early age. The evidence for the role of PMS1 and MLH3 in the disease is weaker than for the five main genes (MLH1/MSH2/MSH6/PMS2/EPCAM); this distinction should be taken into account when interpreting results.

Gene/region examined

MLH1, MSH2, PMS2, EPCAM, PMS1, MLH3, MSH6

Method

Next-Generation Sequencing, CNV Analysis

Accepted sample types

EDTA Blood

Description

7 gene regions associated with Lynch Syndrome are analyzed.

Inheritance

Autosomal dominant, a pathogenic variant in one copy of the gene is sufficient, and the probability of transmission is 50% in each pregnancy.

Related Tests

Inheritance Patterns

Describes how a genetic condition is passed on within a family. There are five main patterns

Go to term →

Carrier (Heterozygous / Homozygous)

Why it matters: In autosomal recessive inheritance, when each parent is a carrier (while both appear healthy), the chance of their child being born with the disease is 25% in each

Go to term →

VUS (Variant of Uncertain Significance)

This is the situation where the test has detected a change in the DNA, but the role of this change in the development of disease is unconfirmed.

Go to term →

How to Read a Genetic Test Result (Positive / Negative / VUS)

A genetic test result falls into three main categories

Go to term →

Types of Genetic Tests

A genetic test is a type of medical test that detects changes in genes, chromosomes or proteins. Today there are more than 77,000 genetic tests available.

Go to term →