DNA and Systemic Diseases
With the completion of the human genome project in 2003 and the decreased cost of DNA sequencing, DNA testing is becoming available and affordable to everyone. More than 1,800 genes associated with disease have been discovered.
With the completion of the human genome project in 2003 and the decreased cost of DNA sequencing, DNA testing is becoming available and affordable to everyone. More than 1,800 genes associated with disease have been discovered. Dental hygienists are concerned with three primary diseases of the oral cavity: caries, periodontal diseases, and oral cancer. Microorganisms and the host immune response are etiologic factors in caries and periodontal diseases; however, recent research has demonstrated a genetic susceptibility to these diseases as well. Research also suggests a genetic relationship to oral cancer.
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The potential to use genetic research to manage systemic diseases through clinical care, improved delivery of preventive oral care, and clinical practice standards for individuals, communities, and global populations is promising. With the advent of oral-systemic links, the genetic basis of systemic diseases and consumer access to affordable DNA sequencing, dentistry and dental hygiene need to become integrated into the genetic arena. Genomic research has provided valuable information in predicting disease occurrence and in creating preventive pharmacogenetic approaches to treating systemic genetic disorders. Oncology uses genotyping and pharmacogenetics. Epigenetics is another area garnering attention, as environmental and maternal stressors during pregnancy influence changes in gene expression without affecting the nucleotide sequence. These changes can manifest in future generations. Suggestions for future genetic studies involve identifying genes that promote good health and increase disease resistance in the presence of environmental risk factors.
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Looking Through the Genetic Lens
Oral health professionals perform assessments and consider the oral-systemic connection when treating patients, but they do not typically look at patients through a genetic lens. Patients may present with a history of cardiovascular disease, diabetes, oral-facial changes, and even periodontal diseases, without ever having undergone evaluation for genetic predispositions to health problems. A three-generational family health history is helpful in assessing disease susceptibility, evaluating the social/psychological impact of health-related genetic information, and identifying and referring individuals for genetic counseling.
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There are two main types of genetic testing: genetic tests available through health care providers and DTC genetic testing. Genetic testing through health care providers involves both salivary and blood samples that are sent to specialized laboratories for analysis. A health care professional provides interpretation of test results and a referral for genetic counseling, if applicable. The cost for this testing may range from $300 to $3,000, but insurance coverage may be available. With direct-to-consumer testing, the individual collects his or her own sample and mails it to a company for analysis. Results are sent back to the individual, and in some cases, a counselor or health care provider may be available by phone or online to answer questions. The cost for direct-to-consumer testing ranges from $100 to $1,000 and it is not covered by insurance.
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Points to Consider
As genetic testing becomes more affordable, consumers can learn more about their propensity toward specific health conditions, be proactive about their care, and share information with health professionals. For those diagnosed with a genetic condition, genetic testing can help improve medical management and offer more information about prognosis and preventive treatment. For some individuals, genetic testing provides a psychosocial benefit of supporting the validity of the diagnosis, as well as offering a support system through genetic disease organizations and counseling. Others may find that there are additional costs as further genetic testing may be needed to define genetic links and for the treatment of the disease. In the process of undergoing genetic testing, family members may learn unexpected information or incidental results concerning disease susceptibility, or they might learn they are carriers of a genetic disease. These findings may lead to unexpected psychosocial issues that require additional levels of counseling and support. Although an individual may present with a genotype for a disease, this does not necessarily mean he or she will actually get the disease.
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As a dental hygiene practitioner, salivary diagnostics may provide a useful tool for determining risk factors for disease, thereby enabling treatment aimed at approaching preventive care from an individualized genetic perspective. Thinking about genetic etiology when analyzing oral conditions would alter the traditional paradigm on how oral health professionals view the oral cavity and disease manifestations. Adding a genetic alert box and a three-generational family history to the health history form would allow for the incorporation of genetic information in the preventive care provided by oral health professionals. With multifactorial diseases— such as cancer, cardiovascular disease, type 2 diabetes, caries, and periodontal diseases—customized treatment plans would include genetic information, environmental factors and exposure, and lifestyle changes. Tobacco use was recently linked to gene-environment interactions. This research has the potential to alter tobacco cessation information and programs with patients in the prevention of oral and lung cancers. Oral health professionals may want to consider creating a handout with genetic resources and genetic counselors for patients who test positive with salivary diagnostics. Informed consent would need to be changed to reflect this type of genetic testing and include GINA guidelines. The development of pharmacogenetics is a promising future as customized drug and adjunctive therapies for oral cancer, periodontal diseases, and caries based on an individual’s genetic profiles would be possible.