RESUMO
BACKGROUND: Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare childhood cancer predisposition syndrome resulting from biallelic germline mutations of mismatch repair (MMR) genes. CMMRD syndrome is characterised by early onset malignancies in children. CASE: Here we present affected children of consanguinous parents diagnosed with CMMRD syndrome due to germline bi-allelic MSH 6 gene mutations with café au lait spots and multiple family cancers from Turkey and reported cases with CMMRD syndrome associated MSH 6 mutation in English literature. Hence, we reviewed English literature from 1990 to 2020 using Pub-Med database. Keywords used to search included constitutional mismatch repair deficiency syndrome, childhood cancer and MSH 6 gene mutation. CONCLUSIONS: We emphasize that the inclusion of CMMRD syndrome in the differential diagnosis of a patient who presents with cafe´ au lait spots and/or hypopigmented skin lesions and cancer especially when consanguinity and/or a history of cancer coexist in children.