The term "common diseases" means those diseases that occur relatively commonly in
the general population, such as diabetes,
hypertension, collagen disease (such as lupus erythematosus), inflammatory
bowel disease (e.g. Crohn's disease), adult heart disease (arteriosclerosis), multiple
sclerosis, etc. These diseases have a combination of genetic and environmental causes.
There is often a "family predisposition", i.e. relatives of patients have a higher
risk for the disease compared to the rest of the population. This risk increases
the more closely one is related to the patient (the patient's first-degree relatives
- children, parents and siblings - are at the highest risk); according to the severity
of the disease (the worse the disease, the greater the risk for relatives), and
the number of patients (the greater the number of patients in the family, the greater
the risk for their relatives).
See also the pages on "Breast cancer" and "Colon cancer".
The risk that these diseases might appear in the future once the child is an adult
depends on the factors discussed above, and whether one or both of the parents has
or will in the future have the disease. It is usually difficult to know when a person
is young and in the fertile period of his/her life whether he/she will develop such
a disease in the future, but an attempt is currently being made to identify the
causative genes, thus allowing a precise estimate of the risk for developing these
diseases to be given. For example, a number of the genes that play a role in the
causation of arteriosclerotic diseases (heart disease due to narrowing of the heart's
blood vessels), cancer and even diabetes have been found, but these are not yet
tested for prenatally.
Environmental factors, such as smoking, obesity, diet, etc. also play an important
part in the development of these diseases. It is already possible to some extent
to prevent the development of some cases of diseases such as breast, ovarian and
colon cancer. Genetic tests for these illnesses are already being performed today
and will be more common in the future.