Pathogenic Variant in Lynch Syndrome-Associated Colorectal Cancer with Polyps.

 Lynch syndrome (LS) is an autosomal dominant condition due to the germline mutation in the mismatch repair (MMR) genes including , , and (post-meiotic segregation increased 2). The MMR mutation carriers have high risk for cancers. Pathogenic variants are rarely reported in LS-associated colorectal cancer (CRC) with colorectal polyps. The aim of the study was to investigate the genetic etiology of CRC in an individual with CRC with multiple colorectal polyps and a family history of cancers.  The index patient was an African male affected by CRC with multiple colorectal polyps. The clinical diagnostic for LS was based on the Amsterdam II criteria and pedigree. Next-generation sequencing with inherited cancer genes panel was used to detect the pathogenic variant.  The patient fulfilled the Amsterdam II criteria and the pedigree revealed a family history of recurrent CRC. A deleterious germline heterozygous mutation c.2192_2196delTAACT was detected.  Our study supports the notion that LS may be associated with polyps and shows the predisposition of heterozygous mutation in LS-associated CRC at young age.