Mismatch repair cancer syndrome (MMRCS) is a cancer syndrome associated with biallelic

DNA mismatch repair DNA mismatch repair (MMR) is a system for recognizing and repairing erroneous insertion, deletion, and mis-incorporation of bases that can arise during DNA replication and recombination, as well as repairing some forms of DNA damage. Mismatch ...

mutations. It is also known as Turcot syndrome (after Jacques Turcot, who described the condition in 1959) and by several other names. In MMRCS,

neoplasia A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

typically occurs in both the

gut Gut or guts may refer to: Anatomy * Abdomen or belly, the region of a vertebrate between the chest and pelvis * Abdominal obesity or "a gut", a large deposit of belly fat * Gastrointestinal tract or gut, the system of digestive organs * Ins ...

and the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

(CNS). In the

large intestine The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being r ...

, multiple colonic polyps develop; in the CNS,

brain tumor A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secon ...

Genetics

Under the name constitutional mismatch repair-deficiency, (CMMR-D), it has been mapped to

MLH1 DNA mismatch repair protein Mlh1 or MutL protein homolog 1 is a protein that in humans is encoded by the MLH1 gene located on chromosome 3. It is a gene commonly associated with hereditary nonpolyposis colorectal cancer. Orthologs of human MLH1 ...

MSH2 DNA mismatch repair protein Msh2 also known as MutS homolog 2 or MSH2 is a protein that in humans is encoded by the ''MSH2'' gene, which is located on chromosome 2. MSH2 is a tumor suppressor gene and more specifically a caretaker gene that code ...

, MSH6 or

PMS2 Mismatch repair endonuclease PMS2 is an enzyme that in humans is encoded by the ''PMS2'' gene. Function This gene is one of the PMS2 gene family members which are found in clusters on chromosome 7. Human PMS2 related genes are located at bands ...

. Monoallelic mutations of these genes are observed in the condition known as

Lynch syndrome Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is an autosomal dominant genetic condition that is associated with a high risk of colon cancer as well as other cancers including endometrial cancer (second most common), ovary, ...

hereditary nonpolyposis colorectal cancer Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is an autosomal dominant genetic condition that is associated with a high risk of colon cancer as well as other cancers including endometrial cancer (second most common), ovary, ...

, while biallelic mutations are observed in CMMR-D. People expressing the HNPCC (which itself is considered autosomal dominant) trait are considered carriers of CMMR-D, thus CMMR-D is classified as autosomal recessive. The term "childhood cancer syndrome" has also been proposed. Café-au-lait macules have been observed.

Diagnosis

Childhood to early adult onset HNPCC + malignant

glioma A glioma is a type of tumor that starts in the glial cells of the brain or the spine. Gliomas comprise about 30 percent of all brain tumors and central nervous system tumours, and 80 percent of all malignant brain tumours. Signs and symptoms ...

s. The polyps developed tend to be larger, fewer, and progress to malignancy earlier than those seen in

familial adenomatous polyposis Familial adenomatous polyposis (FAP) is an autosomal dominant inherited condition in which numerous adenomatous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into c ...

, a clinically similar condition with different underlying mutations. Diagnostic testing consists of a blood sample being collected, and a genetic specialist compares two copies of a patient's gene to normal MMR genes. If there are differences in the genes, the specialists are able to further test and decide if the patient has the deficiency.

Treatment

History

OMIM Online Mendelian Inheritance in Man (OMIM) is a continuously updated catalog of human genes and genetic disorders and traits, with a particular focus on the gene-phenotype relationship. , approximately 9,000 of the over 25,000 entries in OMIM ...

currently includes "Turcot syndrome" under Mismatch repair cancer syndrome. Turcot syndrome is the association between familial polyposis of the colon and

s like

medulloblastoma Medulloblastoma is a common type of primary brain cancer in children. It originates in the part of the brain that is towards the back and the bottom, on the floor of the skull, in the cerebellum, or posterior fossa. The brain is divided into two ...

malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

. It was first reported by

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

surgeon

Jacques Turcot Ancient and noble French family names, Jacques, Jacq, or James are believed to originate from the Middle Ages in the historic northwest Brittany region in France, and have since spread around the world over the centuries. To date, there are over ...

(1914-1977 ) ''et al.'' in 1959 and hence carries the first author's name.

References

External links