Turcot Syndrome


What is Turcot syndrome?

Turcot syndrome is illustrated by the connection of  colonic polyps and tumors in the CNS. It is an unusual hereditary disorder distinguished by the involvement of benign cell growths which is clinically termed as  adenomatous polyps, in the mucous lining of the small, large intestine and rectum and also accompanied with tumors of the central nervous system.

Turcot syndrome


The cause of the development is debatable. Some clinicians have opinion that  Turcot syndrome  has direct link with familial adenomatous polyposis. Familial adenomatous polyposis is an hereditary disorder described by the malignant tissue development in the large intestine and rectum. The onset of Turcot syndrome is due to modification of familial adenomatous polyposis.

But, some clinician believes that Turcot syndrome is completely a different disorder, which has no link with  familial adenomatous polyposis, but has the association with Lynch syndrome. This is an another  hereditary condition, which raise the risk of colorectal cancer. (1,2,3)


Turcot Syndrome Symptoms

In Turcot syndrome, polyp formation is one of the most usual symptoms. Other included symptoms are related to GI tract syndromes, including

  • Diarrhea,
  • Bleeding from rectum (the terminal portion of the large intestine)
  • Exhaustion and tiredness
  • Abdominal spasm
  • Unexplained weight loss

Apart from GI tract related syndrome, individuals having Turcot syndrome may also develop neurological symptoms, which is usually related to brain tumor formation. The symptomatic severity of the nervous system is depending upon the type, site and size of the related brain tumor.

The following are two most frequently obtainable brain tumors in Turcot syndrome are:

  • Glioblastoma. This is a very aggressive form of astrocytoma(one type of brain tumor , where the astrocytes present in the synapse and glial cells are having abnormal cell proliferation). The clinical finding of the glioblastoma is common with Turcot syndrome in association with Lynch syndrome.
  • Medulloblastoma. This type of brain tumor is present in the cerebellum, which is one of the most important segments of the brain. The abnormal cell proliferation is initiated from the granular cells present in the cerebellum. Children are mostly affected with medulloblastoma with a family history of FAP. (1, 2, 3)

Causes

Turcot syndrome is a hereditary condition, which indicates the transferring of the involved gene is continued from generation to generation of the affected family. Depending upon the association of the interrelated genetic disorder, the involved gene is varied, like association with glioblastoma and other characteristics of Lynch syndrome, genetic mutation of involved gene is mainly linked up with MLH1 and PMS2. In contrast with this, if medulloblastoma and other features of FAP affects in a family, then the alteration involved in the APC gene. (1,2)


Diagnosis

If in any family some genetically inherited disorders like colorectal cancer and/or adenomatous colon polyps along with either medulloblastoma or glioblastoma, then the chance of development of the Turcot syndrome is high in the newborn in that family.

Blood tests are offered to gaze for the three genes associated with Turcot syndrome. The recommended blood test to examine the mutation in the APC gene associated with FAP or the MLH1 gene associated with Lynch syndrome is often required to detect the exact underlying abnormal genetic mutation identification. In addition, suspected cases of Turcot syndrome, individual may also need to go for testing of the mutation in PMS2 gene.

If a precise gene mutation is detected, then the same genetic test is performed with the other family members to detect the same abnormality pattern and findings of same genetic mutation abnormality, then it infers the Turcot syndrome is present in the affected person. But, in some cases, without finding of the detectable gene mutation may also conclude the presence of Turcot syndrome.

Other than genetic test, colonoscopy, biopsy of the tumor tissue and X-ray of the CNS for detecting of the brain tumor is conducted. (1,4)

Treatment

The symptomatic treatment usually applied for Turcot syndrome. To prevent the spreading of malignancy, proctocolectomy (surgical intervention of colon and rectum) may conduct. If complete removal of the large intestine is required due to malignant cells spreading, then it is required to additional interventions for rejoining the rectum with small intestine, however this process may not control the relapsing the polyp formation in the rectum. To control the relapsing periodic monitoring of the rectal tissues by signoidoscopy is necessary and any finding of the polyp development should remove or destroyed by surgical or radiation therapy.

Neurological screening is very important for finding out of the brain tumor. The treatment of brain tumor is specific, like site, size and type of brain tumor. Surgical removal is the usual recommendation for brain tumor, but in some cases, additional chemotherapy or radiation therapy is needed, because complete surgical removal may not be possible or chance of spreading of the tumor is higher .

Genetic counseling is usually offered to the affected individual and other family members. Furthermore, the supportive treatment approach should always need to offer in preferential basis to control the discomfort of the patient. (4)


References

  1. Turcot Syndrome; Retrieve from: http://www.webmd.com/cancer/turcot-syndrome
  2. Turcot syndrome; Retrieve from: https://rarediseases.info.nih.gov/gard/420/turcot-syndrome/resources/1
  3. Turcot Syndrome; Retrieve from: http://www.cancer.net/cancer-types/turcot-syndrome
  4. Lionel Jarvis, Nicholas Bathurst, Dev Mohan, David Beckly; Turcot’s syndrome;November 1988, Volume 31, Issue 11, pp 907-914 Retrieve from: http://link.springer.com/article/10.1007/BF02554859?no-access=true

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