POLD1 and Leigh syndrome: Lynch‐like syndrome is nearly identical to LS, as both tumor types have loss of MMR gene expression (via IHC) and are MHL1 methylation negative, but Lynch‐like syndrome patients do not have germline MMR mutations.44, 45, 46 Jansen et al47 analyzed leukocyte and tumor DNA of 62 sLS patients using gene panel sequencing including the POLE, POLD1, and MMR genes.