We identified 1098 MMR gene mutation carriers (420 MLH1, 481 MSH2, 126 MSH6, 53 PMS2 and 18 EPCAM) from 330 families recruited from either family cancer clinics or population cancer registries of the Australasian Colorectal Cancer Family Registry between 1997 and 2012. The gene discussed is MLH1; the disease is cancer.