Whereas medical genetics is the study of the genetics of human disease, clinical genetics deals with the direct clinical care of people with genetic diseases. Clinical genetics encompasses the scientific methods and their application in clinical practice, with the focus on human diseases caused by genetic variation. The principal concerns of clinical genetics include clinical evaluation, diagnosis, genetic counseling, and therapeutic management of genetic disorders. Genetic disorders are typically complex, multiorgan, and systemic in nature, requiring a coordinated approach to the care of affected individuals and their families.
Clinical geneticists are physicians who typically have training in a medical specialty, such as pediatrics, medicine, or obstetrics and gynecology, with extended training in medical genetics. Clinical genetics is now a medical specialty in the field of medical genetics, with board certification and standards of care.
The conditions with which clinical geneticists have traditionally been concerned include chromosomal abnormalities, single-gene disorders, and birth defects. Many conditions are now identified through prenatal diagnosis or genetic screening. But most often, genetic disorders are diagnosed through the referral of an individual to a clinical geneticist by his or her physician. Today, clinical genetics is extended increasingly to common later-onset diseases, such as familial cancer, diabetes, and cardiovascular disease, with more emphasis on preventive measures and behavior modification to delay the onset of the disease.
Areas in which the field of clinical genetics relates to anthropology concern both cultural and biological issues. It is increasingly evident that genetic health care services need to be provided by professionals who are culturally competent. Providers of genetics health care should understand culture-based beliefs and attitudes about disease, including genetic disorders, in order to deal effectively with the needs of families. In the assessment of individuals, clinical geneticists often use anthropometric measurements, a traditional tool of biological anthropology, especially in the evaluation of craniofacial dimensions that are important in the diagnosis of many genetic disorders. In addition, clinical geneticists evaluate the physical growth of children, the focus of a traditional research area in biological anthropology, as body growth and size frequently vary from the norm in genetic disorders.
Perhaps there never has been a stronger contribution to the field of clinical genetics than the Human Genome Project (HGP). It is estimated that there are now almost 1,000 diseases for which genetic tests are available. Included in this estimation are a number of the common, complex diseases such as cardiovascular disease and cancer. The HGP has created a human genome map with approximately 35,000 human genes. Almost one third of these genes have been discovered, with many of the gene loci, allelic variants, functions, and disease associations described. The HGP has enabled researchers to identify errors in genes that may contribute to or cause certain diseases. By the year 2010, predictive genetic testing might be available for more than 25 common diseases, such as diabetes and hypertension. This very expectation will impact genetic counseling and testing, in which individuals will seek information to take steps to reduce the risks for certain genetic diseases. For example, cardiovascular disease is a complex interaction of genetic factors (gender, family history, single-gene abnormalities of lipids, diabetes, obesity, and hypertension) that interact with nongenetic risk factors (smoking, physical inactivity, stress, and increasing age). In the future, an individual might seek genetic counseling and testing to determine susceptibility to cardiovascular disease in order to make lifestyle modifications. More important, the identification of disease-related genetic variation plays a role in the prevention of disease and will reshape the future of health care.
References:
- Davies, K. (2001). Cracking the genome: Inside the race to unlock human DNA. Baltimore: John Hopkins University Press.
- Nehring, W. M. (1999). Clinical genetics: An overview. The Journal of Cardiovascular Nursing, 13, 19-33.
- Wilson, G. N. (2000). Clinical genetics: A short course. New York: Wiley-Liss.
