Can we use genetic screening of healthy populations to save lives and prevent disease? Join the conversation.Posted on by
On January 30, 2017, CDC held a special workshop to discuss the role of public health in the implementation of genetic screening programs beyond the newborn period. The workshop brought together panelists from the worlds of medical genetics and public health practice, including cancer, birth defects, and laboratory science. Workshop presenters and a CDC panel discussed the current status of genetic screening in the United States in the newborn period and the possibility for a public health screening program beyond newborns. Newborn screening is currently the largest public health genetics program in the world. Every year, more than four million babies are screened at birth for 30 or more genetic, metabolic, and other conditions—such as phenylketonuria, sickle cell disease, and cystic fibrosis—that lead to disability, morbidity, and mortality.
With the launch of the precision medicine initiative, millions of people will have their genomes sequenced. But even before such a project leads to new discoveries, we already know that many people have genetic mutations that make them more likely to get cancer, heart disease, and other conditions. We have written about some of these conditions before, notably familial hypercholesterolemia, hereditary breast and ovarian cancer, and Lynch syndrome, which collectively affect more than two million people in the United States.
Recent studies (see examples, here and here) are showing that these conditions are more common than previously thought, may not be adequately diagnosed as part of regular healthcare, may not be associated with strong family history for these conditions, and many affected people and their at risk relatives are not undergoing recommended treatments or preventive interventions that can prevent early deaths from cancer or heart disease. In addition, disparities in implementation of existing evidence recommendations exist by race, ethnicity, and geographic location. The American College of Medical Genetics and Genomics (ACMG) has published an updated panel of 59 genes with clinically actionable mutations that they recommend be returned to people undergoing genome sequencing studies. The list of genes includes the ones for the three genetic conditions mentioned earlier, as well as several others. Mutations in the original ACMG panel of 56 genes are common in the population. A recent study shows that more than 1% of the population carry pathogenic mutations in these genes and are at increased risk of common diseases, regardless of their family history.
To be sure, while the use of genome sequencing is promising in certain clinical scenarios, such as rare diseases and cancer, we do not think that whole genome sequencing in the general population is appropriate at this time. We would not recommend its use outside research studies. We have written about this before and we do not mind repeating this opinion here. But it is also becoming clearer that as science progresses, we are discovering more opportunities for using genetic screening of healthy individuals for preventing common diseases across the lifespan, outside the newborn screening context. We encourage a much-needed dialogue to assess what, when, and how genetic screening of populations should be used to prevent disease and save lives in the not too distant future.
The January 30 workshop is part of a long-term conversation that the CDC Office of Public Health Genomics would like to initiate. We have posted the presentations from our speakers here. We will be posting soon the presentations from our speakers and hope to continue the dialogue using responses to this post and other means. We would like to explore the role of the public health system in working with healthcare providers, payers, policy makers, and the general public to ensure that people at increased genetic risk and their relatives get appropriate counseling and life-saving interventions. Questions that need to be addressed include:
- What lessons can we learn from other population-screening programs including newborn screening programs?
- What would be the potential benefits, harms, and costs of an organized public health effort?
- What laboratory platforms should we use (e.g. sequencing the whole genome or selected genes only that we know lead to high risk of preventable conditions)?
- How can we ensure the quality and access of the testing process?
- What are the ethical, legal, social, financial, and economic implications of genetic screening outside the newborn context?
- What infrastructure is needed to implement population-based genetic screening?
Join the conversation and post your comments, suggestions and issues here.
6 comments on “Can we use genetic screening of healthy populations to save lives and prevent disease? Join the conversation.”
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It will be a very interesting discussion. Please make the distinction between (a) making available such tests for asymptomatic citizens so that it is available to them if they (for whatever reason) seek an appointment with a physician and ask for it and (b) reaching out to the public and encouraging them to participate in some form of genetic testing programme with the implication that those who instigate it (whether the state or a particular physician) believe it to be of value. My own view is while there could be justification for the first model, outwith neonatal screening we are far from having the evidence to recommend the second. From a semantic perspective I would only use the term ‘screening’ to refer to the second, although there are many who would use the term to refer to any tests on asymptomatic individuals.
Start with small populations. We have so many ethnic groups
My comments would be on the platforms, the data and the financial impact.
I hope the platform and the focus will not be whole genome sequencing but only targeted at specific genes for specific populations.
I hope the screening is accompanied by relevant statistics like say if we have a high incidence of ovarian cancer in certain ethnicities then sequence oncogenes associated with that cancer.
Also the data handling and mining to convert it into information that a physician can use needs to be clearly formulated.
My last comment is about the cost and willingness of mainstream existing healthcare financing mechanisms both private and public to fund such public health genomics projects
Our experience with NBS suggests that we should proceed with great caution. Most NBS happens in the absence of parental informed consent. Further, NBS mixes up screening with the possibility of benefit to the child, with screening for purely research purposes. The latter makes the absence of consent even more egregious.
The more traits we test for, the more consent should be required, and yet the opposite appears to be the case. The more complex the testing, the more impossible it seems to inform parents.
I find this parallel to the old argument that screening (like in self breast exams) contributes to the problem and should not be performed by those without clinical training. The idea being practiced by the masses becomes “ignorance is bliss” or “what you don’t know cant hurt you.” We are stuck wondering: At what point does genome screening become indicated? instead of, What can genome screening do for us? Research requires big numbers. We are refining the speed of access and quality of the data rapidly. We may not be uncovering a clinically significant amount of cases that benefit from “screening”, but we are building data for a revolutionary medically significant diagnostic tool. To answer the question, Yes, we can we use genetic screening of healthy populations to save lives and prevent disease.
This genomic screening for general public has a potential to detect genetic mutations causing diseases such as cancer and cardiac diseases. It seems logical that they can improve the health and wellness of general population.
My suggestion would be to
1.Screen only those disorders where prevention measures are available
2. Screen only those mutations which are known to be pathogenic
3. Pre test and post test counselling should be mandatory by a clinician who can interpret the implications of the tests
Hence guidelines similar to newborn screening should be developed by a consensus between clinicians and molecular scientists and clinical geneticists
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