Phenotype Comparison of MLH1 and MSH2 Mutation Carriers in a Cohort of 1,914 Individuals Undergoing Clinical Genetic Testing in the United States

In this large study of mismatch repair gene mutation carriers from the United States, MLH1 carriers had more colorectal cancer than MSH2 carriers whereas endometrial cancer prevalence was similar. Large genomic rearrangements were more frequent in the MSH2 gene. MSH2 carriers and their relatives have more extracolonic nonendometrial Lynch syndrome-associated cancers and may benefit from additional screening.