The Role of Genes in Diseases
Genes are the thing that determines your unique traits from the inside out. As a result, genes do not only determine the way you look but the way your body functions too. They play an important role in your overall health but they can also make you more susceptible for certain health problems and diseases, in the first place those that run in your family. If one of your parents has diabetes mellitus or cancer, you are more likely to develop it yourself. However, just because you carry certain genes that does not necessarily mean that you will develop a condition which is closely related to that particular gene. Most diseases are a result of a combination of multiple factors including dietary, lifestyle and environmental factors. However, it is also possible to develop health problems exclusively due to genetic abnormalities and mutations.
Health problems caused by genetic abnormalities and mutations are relatively rare and are usually divided into four categories: autosomal dominant, autosomal recessive, X-linked and Y-linked genetic disorder. The autosomal dominant genetic disorder requires only one abnormal gene which is inherited from an affected parent. Examples of autosomal dominant genetic disorder include the Huntington’s disease, Marfan syndrome and breast cancer, while the chances to inherit this genetic disorder are 50:50. The second type of genetic disorder, autosomal recessive disorder involves at least two copies of an abnormal gene from “carrier“ parents (each having one mutated gene). Examples of this genetic disorder include Niemann-Pick disease, Roberts syndrome, sickle-cell disease and cystic fibrosis. This disorder is inherited by 25 percent of children. 50 percent of children become “carriers“, while the rest 25 percent are not affected.
The X-linked recessive genetic disorder refers to a genetic abnormality involving the X chromosome. This disorder is passed by a “carrier“ mother. 1 out of 4 children of unaffected “carrier“ mother will develop X-linked recessive disorder, 1 will be a “carrier“, while 2 will be unaffected. Daughters of affected father and unaffected mother become “carriers“ of this genetic disorder and may pass it to their children. Sons cannot inherit this genetic mutation which can cause haemophilia A, colour blindness, Lesch-Nyhan syndrome and Duchenne muscular dystrophy. However, they can inherit the Y-linked disorder which is passed from affected fathers to sons but this genetic disorder is very rare.
In addition to the above mentioned genetic disorder, the genes you inherit from your parents can also make you more susceptible to certain health problems and diseases including some types of cancer, autoimmune diseases, asthma, diabetes, obesity, etc. There are simply too many health problems associated with genetic factors to be able to list them all. However, just because you have inherited a “cancer“ gene for instance that does not mean that you will actually develop it. The scientists do not know why some people with certain genetic predispositions develop a certain illness and the others do not. However, people with a strong family history of certain medical conditions are usually recommended genetic testing in order to assess the risk and start preventive treatment.