Lynch syndrome is a rare disorder. The condition is named after Henry Lynch, a doctor and authority on inherited cancers. The estimated proportion of all CRCs that are caused by Lynch syndrome depends on how this syndrome is defined, with traditional definitions being based on family history and age of onset. It is also known as hereditary nonpolyposis colorectal cancer syndrome(HNPCC). It is caused by mutations or alterations of particular genes. Lynch syndrome strongly predisposes people who have this inherited defect to develop colorectal cancer as well as several other types of cancer. The genes associated with HNPCC can sometimes cause other cancers, such as stomach, ovary, endometrium (the lining of the womb) and kidney. HNPCC is an inherited cause of cancer of the bowel. The HNPCC syndrome is due to mutation in a gene in the DNA mismatch repair system, usually the MLH1 or MSH2 gene or less often the MSH6 or PMS2 genes. The syndrome is classified as Type I in the absence of extracolonic cancers and Type II if these are present. However, sarcomas have rarely been described in these families. The cancers of the colorectal area associated with the Lynch Syndromes usually develop at a younger age than is normally found in other persons with colorectal cancer.

The syndrome is neither common nor rare, occurring in one or two of every 1,000 people. Women with HNPCC have a 20-60% lifetime risk of endometrial cancer. In HNPCC, the gastric cancer is usually intestinal-type adenocarcinoma. Other HNPCC-related cancers have characteristic features: the urinary tract cancers are transitional carcinoma of the ureter and renal pelvis; the small bowel cancer is most common in the duodenum and jejunum; and the most common type of brain tumor is glioblastoma. When colorectal cancer is associated with Lynch syndrome, it tends to occur at a younger age than in most other colorectal cancer cases. Colorectal cancer associated with Lynch syndrome tends to occur in people at a younger age than for people with the more common nonhereditary forms of colorectal cancer. Family history can provide important clues to the presence of the Lynch syndrome. Different segments of the DNA strands contain genes responsible for different structures and functions in the body. For example, certain segments of DNA carry genes that determine one's eye color, hair color, height, and other physical characteristics. Other DNA segments of DNA carry genes that regulate the duplication and the rate of growth of cells.

Causes of Lynch syndrome

The common causes and risk factor's of Lynch syndrome include the following:

Lynch syndrome is caused by mutations or alterations of particular genes.

Age is the primary risk factor.

If you have a family history of Lynch syndrome, you're at much greater risk of inheriting this condition yourself.

Daily alcohol use (may double the risk).

Eating a high-fat, low-fiber diet.

Genetic disorders such as familial polyposis syndromes and hereditary non-polyposis colon cancer syndrome (HNPCC).

Not having periods, or not having them often.

Smoking is also a risk factor for Lynch syndrome.

Symptoms of Lynch syndrome

Some sign and symptoms related to Lynch syndrome are as follows:

Changes in bowel habits- for example, constipation or diarrhea that persists for longer than several days.

Change in appetite.

Abdominal pain and even an abdominal mass.

Feelings of fatigue or weakness.

Black, tarry stool, which may represent bleeding above the rectum.

Iron deficiency without another identifiable cause.

Rectal bleeding.

Fatigue associated with anemia.

Treatment of Lynch syndrome

Here is list of the methods for treating Lynch Syndrome:

When polyps associated with Lynch syndrome are present, doctors remove them during a colonoscopy.

Chemotherapy, which uses drugs to destroy cancer cells. This approach often follows surgery.

Surgery may also be an option in people who carry the genetic mutation of Lynch syndrome, even if they don't yet have colorectal cancer.

The standard treatment is to give radiotherapy after surgery to women in certain circumstances.

Most people with Lynch syndrome choose frequent colonoscopies over prophylactic surgery.