"Genetic" pertains to the study of human genes, the discrete parts of DNA that shape individual and species characteristics. In a human being, probably less than 1% of a person's DNA actually is utilized to provide instructions to human cells.

Several human diseases are the direct result of genes inherited from a person's parents. Some diseases and disorders are almost always transmitted from parents to children of both sexes (e.g. dwarfism). Others require both parents to pass a particular recessive gene to the child (e.g. cystic fibrosis). Still others are almost only passed on to males, but the defective gene is actually on the mother's X-chromosone (e.g. hemophilia, color blindness).

In addition, some genes make it more likely that a patient will develop a particular disease. This includes conditions such as diabetes mellitus, heart disease and most forms of cancer. As such, doctors taking a medical history almost always ask what diseases the patient's parents and other close relatives are known to have suffered from.

Once a patient has been diagnosed with a genetic condition, there is generally no treatment that will eliminate the disorder. Patients with such diseases generally have to undergo a lifelong course of treatment. For example, sufferers of cystic fibrosis, which causes the mucous to become thickened, must undergo a course of several medications designed to both thin out the mucous so the patient can breath normally, as well as other medications that assist the patient to digest food.

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