Genetic Screening

Genetic screening and testing refers to any modality that determines an individual’s DNA “blueprint” along with any variation from a determined reference sequence or code. Understanding one’s genetics and any variations that are present can allow for tailored interventions to prevent or treat disease or disease complications. Appropriate use of genetic testing, including understanding the limitations and challenges of available testing approaches, is crucial to the successful use of genetic testing in improving health and quality of life.

The extent of genetic testing can range from analyzing a single variant (such as the variant for factor V Leiden which we test among those with Deep Vein Thrombosis or a Pulmonary Embolus) to analyzing the entire genome. The appropriate test depends on the indication or presenting feature(s), the tests available for the suspected condition(s), the available information regarding the genetic cause(s) of the condition or presenting features and cost. Traditionally, the expense to sequence an individual’s entire genome has been prohibitive ($10,000+) although more recently this cost has decreased into the $800-$1000 range.

Testing can be performed at different times during a patient’s life and for different purposes (diagnosing a disease, predicting disease risk, or determining carrier status for highly predictive genes such as BRCA 1 and 2 for breast cancer). Testing to determine germline genotype (derived from birth) can be performed on blood or saliva containing buccal (cheek) cells. 

At Santa Monica Primary Care, the most exciting and informative use of Genomic Medicine would be in predictive testing – that being a method of risk assessment for unaffected individuals who are at risk of developing conditions with a heritable component.  Knowledge of this increased risk may lead either to interventions to decrease the risk, or more frequent surveillance in order to identify it early.

While many companies (including direct to consumer approaches) exist, we have chosen to work with the GET DNAbled Program (https://getdnabled.com/index.html) as a result of their technical and consultative expertise. They combine whole genome sequencing with a patient’s personal and familial medical history to identify specific risk factors as well as develop an actionable plan of care. For genetic screening to be successful, it must  be coordinated with appropriate counseling to help patients understand the implications of a positive or a negative result not only for themselves but also for their family members. It is important to note also that the United States Affordable Care Act (ACA) prohibits variations in health insurance premiums based on health status and genetic information.

Generally, germline genetic testing does not need to be repeated for a specific gene as long as the results are accurate, since germline DNA sequence does not change. But as new advances occur in genetics, the information this testing provides can be expanded and refined over time without any additional sample needing to be obtained.