Lynch syndrome is an inherited genetic, autosomal dominance condition. It is also known as hereditary nonpolyposis colorectal cancer. The persons affected by this condition have an inherited higher risk of developing colorectal cancer or colon cancer. These persons are also at a higher risk of developing other cancers like endometrial cancer, ovarian cancer, kidney cancer etc. also, these persons develop cancer at an early age or an age which is otherwise unusual for that particular type of cancer to develop.
How Do You Inherit Lynch Syndrome?
In normal scenario, each cell in our body carries two copies of every gene- one is inherited from the father and one is inherited from the mother. Any autosomal dominant condition means the gene mutation needs to be present only in one copy of gene for a person to acquire an increased risk of that particular disease. This in other words means that one parent having a gene mutation can pass one copy of their healthy gene or one copy of their mutated gene to their children, thus passing a 50% chance of inheriting that mutation to the children. If one has the mutation, then his parents and siblings also have a 50% chance of acquiring that mutation. However, the parents may test negative too and in this case the chances of the siblings inheriting the mutation decrease significantly. But the risk is not completely eliminated compared to other normal persons. It is still normally higher for them.
Now, for example, SAM and JANY get married. Sam is affected by HNPCC or lynch syndrome, while Jany is a perfectly normal person. They have three children. As Sam is affected, he passed a 50% chance to his children. Out of the three children, two inherited the gene mutation from Sam. Now they got married to healthy persons. Out of the three, the two who inherited the gene mutation will again have a chance of 50% for passing the gene mutation to their children. The child who was healthy will not pass any mutated genes to his children.
What Exactly Happens In Lynch Syndrome?
Our body is made up of cells. Our cells contain genes and genes contain DNA. Normally, each cell contains two copies of genes, one each inherited from mother and father. These genes contain DNA. This DNA has a set of instructions for all the chemical activities going on in our body. As our cells grow and divide, the cells make copies of the DNA. In this process, some minor mistakes can happen. These mistakes are corrected and repaired by a certain type of genes- these genes are known as mismatch repair genes. However, if these genes get mutated, then they cannot do their work of repairing properly and as a result the mistakes keep on copying and a large pile of mistakes get created. This results in formation of further gene damage and as a result the cells become diseased and turn cancerous.
This is exactly what happens in lynch syndrome. The genes that are mutated in lynch syndrome are the mismatch repair genes. These are in fact the genes that stop us from getting cancer. If these genes are mutated, their functioning of making repairs will get compromised, which results in an increased risk of getting cancer for a person. Thus, the person who inherits lynch syndrome, is put at an increased risk of acquiring certain cancers, especially colorectal or colon cancers, and other cancers like endometrial cancer, ovarian cancer, kidney cancer etc.
Lynch syndrome or HNPCC is not a cancer in itself, but it’s a condition that raises one’s risk of getting cancers considerably; and at a younger age too, than most other people. If any family history is noted, it must be brought to the immediate notice of the physician so that the risk can be decreased; and the cancers can be prevented.
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