{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"MutS homolog 2 (MSH2) is a mismatch repair (MMR) protein. MSH2 can form heterodimer with mutS homolog 6 (MSH6) to form MutS⍺. It can also dimerize with mutS homolog 3 (MSH3) to form MutSꞵ. Both MutS⍺ and MutSꞵ identify and fix DNA mismatches. Defective MMR, due to MSH2 mutation, can lead to the accumulation of numerous replication errors, particularly in short nucleotide repeat sequences (microsatellites). This accumulation of errors, resulting in microsatellite instability-high (MSI-H), is the molecular basis of the replication error positive phenotype seen in hereditary non-polyposis colorectal cancer (HNPCC or Lynch syndrome)."}]}]}