Firstly, the common dMMR signature, enriched for 1 bp indels and the SNV-signature MMR1; these associations involved, e.g. the Lynch syndrome genes MSH2 and MLH1, and some additional genes, e.g. MTOR and SETD2. Secondly, a distinct set of associations involved a mutational component enriched for 2 bp and longer indels, but did not encompass a notable increase in SNVs, involving the core MMR gene MSH3, and additionally MLH3, EP300, and PIK3C2B. Here, MLH3 is linked to Lynch syndrome.