MSH6 and Leigh syndrome: The results showed that the TMB of samples with MSH2 and MSH6 germline variants in the CNS LS-related tumor and Non-CNS LS-related tumor groups was greater than that in the Non-CNS LS-unrelated tumor group (p < 0.001), and the TMB of samples with PMS2 germline variants in the Non-CNS LS-related tumor group was greater than that in the Non-CNS LS-unrelated tumor group (p < 0.005).