Constitutional Mismatch Repair Deficiency Syndrome

**Semantic type:** Disease or Syndrome

**Definition:** A rare childhood cancer predisposition syndrome caused by biallelic inheritance of mutations in MLH1, MSH2, MSH6, or PMS2 genes. It is characterized by the development of childhood cancers, usually hematological malignancies and/or brain tumors, and colorectal cancers with multiple intestinal polyps. The majority of patients show signs of neurofibromatosis type 1.

**Synonyms:** - BMMRD - Biallelic Mismatch Repair Deficiency - Biallelic Mismatch Repair Deficiency Syndrome - CMMR-D - CMMRD - Constitutional MMR Deficiency - Constitutional Mis-Match Repair Deficiency Syndrome - Constitutional Mismatch Repair Deficiency