How is Lynch syndrome inherited?
We all have two copies of every gene, including two copies each of MLH1, MSH2, MSH6, PMS2, and EPCAM. We inherit one copy of each gene from our mother and one copy from our father. When working properly the MLH1, MSH2, MSH6, PMS2, and EPCAM genes help to reduce cancer risk. People with Lynch syndrome have a gene change (mutation) in one of their MLH1, MSH2, MSH6, PMS2, or EPCAM genes that cause the gene not to work properly. A non-working copy of the gene leads to increased risk for cancer. If a parent has Lynch syndrome, there is a 50% chance that each of his or her children will also have Lynch syndrome. This is called autosomal dominant inheritance.
SOURCE: Emory University - Department of Human Genetics in collaboration with ThinkGenetic • https://www.thinkgenetic.com/diseases/lynch-syndrome-i/inheritance/2193 • DATE UPDATED: 2020-01-09
Kohlmann W, Gruber SB. Lynch Syndrome. 2004 Feb 5 [Updated 2018 Apr 12]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1211/