Genetic and clinical determinants of constitutional mismatch repair deficiency syndrome: report from the constitutional mismatch repair deficiency consortium.

Background: Constitutional mismatch repair deficiency (CMMRD) is a devastating cancer predisposition syndrome for which data regarding clinical manifestations, molecular screening tools and management are limited.

Methods: We established an international CMMRD consortium and collected comprehensive clinical and genetic data. Molecular diagnosis of tumour and germline biospecimens was performed.