by Tabitha Poorvu, MS, LCGC
Our growing number of genetic counselors are committed to being on the leading edge of genetic screening and testing options that are available to patients. As such, several of our prenatal and cancer genetic counselors went to the National Society of Genetic Counselor’s Annual Education Conference in Pittsburgh this past October to learn about advances in the field. Here we have summarized a few of the latest findings in the field of genetic counseling that are effecting how we counsel patients at IMG.
The Future of Cell-Free DNA Screening: As noted previously in this newsletter, cell-free DNA testing is expanding. Here at Insight Medical Genetics, we feel that offering this expanded screen will give patients significantly more information than the currently available options. However, the screening comes with significant limitations and we feel that it is crucial that patients get comprehensive pre-test counseling from a genetic counselor that is knowledgeable regarding the possible outcomes.
As opposed to aneuploidy where maternal age is correlated with chromosome conditions, microdeletions and microduplications occur in all pregnancies at the same frequency (~1.6%). Therefore, a 22 year old patient has the same risk as a 42 year old patient for one of these conditions to be present. Some of these conditions, like DiGeorge syndrome (22q11.2 microdeletion syndrome) have structural anomalies (tetralogy of fallot, cleft lip/palate) associated with them, but others do not have any visual indicators on ultrasound that one may be present.
The Future of Cancer Genetics: As more people with a personal and/or family history of cancer elect genetic testing on multi-gene cancer panels, we continue to see the phenotype of various cancer predisposing conditions widen. In some cases, the guidelines are straightforward, but in others we must look to the family history to dictate screening protocols for an individual.
If a person is found to have a deleterious mutation in a cancer predisposing gene, but there is no family history, the risk for an individual to develop cancer might not be as high as what was originally determined in the highly penetrant families that have been identified thus far.
Similarly, if a patient does have a very strong family history of cancer, but has screened negative on a multi-gene panel, it is still extremely important, maybe more so, for that individual to speak with a genetic counselor and develop a personalized screening protocol based on family history even in the absence of a known deleterious mutation. In fact, these are often the patients that are lost to follow-up since they were not identified as "increased risk."