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Uses of Genetics


Quasar S. Padiath

, MBBS, PhD, University of Pittsburgh

Reviewed/Revised Jun 2023 | Modified Oct 2023

Genetics can be used in several ways to better understand, diagnose, and treat various disorders.

Understanding disorders

The potential for understanding human genetics increased greatly when the scientists behind the Human Genome Project successfully identified and mapped all the genes on human chromosomes in 2003. Genetic techniques can be used to study individual genes to learn more about specific disorders. For example, some kinds of disorders that have been classified based on what symptoms they caused have been reclassified based on what the genetic abnormality is.

Diagnosing disorders

Diagnosing genetic disorders before birth

Advances in techniques that assess people’s genetic characteristics and increased understanding of human genetics have improved diagnosis of genetic disorders before birth. In some cases, genetic disorders that are diagnosed before birth can be treated after birth or sometimes before, which prevents future complications. For example, corticosteroids given to the mother before birth may decrease the severity of a type of genetic hormone deficiency in the offspring.

Did You Know...

  • Genetics may be able to help predict what disorders a person is likely to develop or how the person will respond to certain treatments.

Responding to drugs

Increased understanding of human genetics has the potential to predict how people, depending on their precise genetic makeup, will respond to certain drugs (Genetic Makeup and Response to Drugs Genetic Makeup and Response to Drugs Differences in genetic (inherited) makeup among individuals affect what the body does to a drug and what the drug does to the body. The study of genetic differences in the response to drugs... read more ). For example, specific genes can predict how much warfarin, an anticoagulant ("blood thinner"), a person is likely to require. This prediction is important because taking too much warfarin can cause serious bleeding and taking too little makes the drug ineffective, which is also risky.

Gene analysis can also predict whether a person will have intolerable or only minor side effects when taking irinotecan, an anticancer drug. People likely to have intolerable side effects can be treated with a different drug.

Gene analysis can also determine how quickly people metabolize and thus respond to codeine, an analgesic. People who metabolize codeine rapidly can accumulate high levels of a metabolic byproduct of codeine that impairs their unconscious drive to breathe. This effect of rapid metabolization resulted in the death of some children who were given codeine after tonsillectomy and adenoidectomy were done to treat obstructive sleep apnea.

Treating diseases

The genetics of diseased tissue (such as cancers) can help drug manufacturers identify more precise treatment targets when developing drugs (such as anticancer drugs). For example, the anticancer drug trastuzumab can target specific cancer cells in breast cancers that involve the breast cancer gene HER2/neu.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  • Human Genome Project: Information about the international, collaborative research program mapping and understanding all of the genes of human beings, known as the human "genome"

Drugs Mentioned In This Article

Generic Name Select Brand Names
Coumadin, Jantoven
No brand name available
Herceptin, Herzuma, KANJINTI, Ogivri, Ontruzant , Trazimera
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