The international prospective IMPACT study evaluated PSA levels and PCa occurrence rate with P/LP variants in DNA MMR genes, MLH1, MSH2, MSH6 and PMS2, in a cohort of 899 patients predominantly of European ancestry: MLH1, 204 patients; MSH2, 305 patients; and MSH6, 135 patients. The gene discussed is MRC1; the disease is posterior cortical atrophy.