Introduction
The second most common type of cancer is colorectal cancer. In about thirty-five percent of patients, it has been shown to have a close association with genetic factors. Some patients might have a known genetic factor like Lynch Syndrome (a condition where colorectal cancer or endometrial cancer develops at a young age), Familial adenomatous polyposis (FAP, an inherited condition that affects the gastrointestinal tract), and MUTYH-associated polyposis (MAP, a genetic disorder where polyps appear in many parts of the body).
What Is Mutyh-Associated Polyposis (MAP)?
MUTYH-associated polyposis is a rare inherited condition that causes the formation of polyps all over the body. Polyps are abnormal growths seen in the body. A person can have from ten to five hundred polyps. They can turn cancerous if not treated appropriately. A number of polyps can grow in the colon, rectum, small intestine, or stomach. It is passed on from parents to their children, being an inherited condition. The risk of colorectal cancer is high in people with this condition. In addition, they are also at increased risk of developing cancers of the stomach, small intestine, ovary, endometrium, bladder, liver, thyroid, and skin.
What Are the Causes of Mutyh-Associated Polyposis (MAP)?
MUTYH-associated polyposis is an inherited condition. It is passed on through genes in an autosomal recessive pattern. In an autosomal recessive condition, the condition is expressed only if the character is inherited through both parents. The MUTYH gene is found to be altered in this condition. The condition is not expressed if one gene is inherited, as it is a recessive character. The patient might not have MAP but is a carrier of the condition. A carrier can pass the condition on to their children only if their biological partner also carries it. Studies show that one to three percent of people remain as carriers. They also have an increased risk of colorectal cancer. However, the risk remains lower than that of those with the condition.
How Is Muyth-Associated Polyposis Inherited?
When both parents are carriers of the condition, there is a higher risk that their children can inherit the condition. The risk is seen to be as follows:
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Twenty-five percent of cases may not develop the condition at all. They might not inherit the mutated MUTYH genes.
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Fifty percent chance of being a carrier. They might not have the condition but can carry the condition and pass it on to their children.
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Twenty-five percent chance of having the condition. This usually occurs when both biological parents carry the mutated MUTYH gene. They can pass at least one mutated gene to their children.
What Are the Symptoms of Muyth-Associated Polyposis Inherited?
The condition may not show any specific signs or symptoms. The polyps may be present in the abdomen but may not show any signs. The presence of polyps in the gastrointestinal tract alone might not be sufficient to decide that a person has MAP, as there are other conditions with similar symptoms, like familial adenomatous polyposis (FAP). FAP is an inherited condition where polyps are found within the gastrointestinal tract). These conditions can be identified only by a genetic test.
How Is Muyth-Associated Polyposis Diagnosed?
There are multiple steps in diagnosing the condition. The healthcare provider might take a detailed case history, including details on family history. This can include the health status of the biological parents, grandparents, and siblings. If a genetic condition is suspected, genetic tests might be recommended. Genetic tests help identify genetic conditions like MUTYH-associated polyposis. Genetic tests can be recommended if:
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There is a strong history of colorectal cancer.
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Other members of the family have genetic conditions like MAP, FAP, etc.
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Multiple siblings have gastrointestinal polyps or other gastrointestinal abnormalities, while the parents do not. (Parents can be carriers).
If identified as having any genetic conditions, the healthcare professionals might advise further screening for cancer and other related conditions. The screening options for MAP can include:
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Colonoscopy: An examination procedure where the inner parts of the large intestinal and the distal part of the small intestine are observed. A long, flexible tube called a colonoscope is used for this. It is advised every one to two years after the age of 25 to 30 years. It is advised more frequently once polyps are observed. This aims to remove the polyps. Surgery might be considered if there are many polyps in the gastrointestinal tract.
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Esophagogastroduodenoscopy (EGD): This procedure is done to view the oropharynx, esophagus, stomach, and proximal duodenum. It is advised after 25 to 30 years, or once diagnosed, of colorectal polyps.
How Is Muyth-Associated Polyposis Managed?
There is currently no complete cure for the condition. However, if diagnosed at an early stage, the risk of becoming cancerous can be steadily reduced.
A colonoscopy can be done to remove polyps after diagnosis. A gastroscopy will be advised if the polyps are present in the duodenum. Gastroscopy is a procedure where a long flexible tube is inserted to visualize the upper part of the duodenum. If there are fewer polyps, they can be removed using these procedures. However, surgery might be required to remove them if they are numerous. There are three surgical procedures used to remove these polyps, which include:
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Colectomy with Ileo-rectal Anastomosis (IRA): This is done when the rectum has minimal inflammation and is distended. The colon is removed, along with the joining ileo-rectal sections.
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Restorative Proctocolectomy (J-Pouch): The entire rectum and colon are removed in this procedure. The sphincter and the anus are preserved.
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Total Proctocolectomy with a Permanent Ileostomy (TPC): This is only done in exceptional cases. This is the last resort when all other treatments fail to help with the large intestine.
Conclusion
Being a genetic condition, there is currently no cure. There are no existing methods to prevent it from being passed on to further generations, either. However, assisted reproductive procedures can help to lower the risk of a child getting the condition. A procedure called in vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD) can reduce the risk of the child developing this condition. In this procedure, the embryo is tested for any genetic abnormalities before being implanted into the uterus. The procedure may have many financial and emotional considerations behind it. Diagnosing the condition early helps to manage it better.
