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Introduction to Genetics and Public Health
Heather Creswick, M.S.
John Quillin Ph.D.
Is genetics relevant for you? You might be surprised. Listen to this podcast and find out as well as this one from Dr. Francis Collins (here for audio link).
Objectives:
After reviewing these materials, you will be able to:
- Explain, in broad terms, genetics and genomics and how they relate to the essential functions of public health.
- Describe three concrete examples (case studies) of how genetics can be applied to public health.
- Improve your self-assessed public health competency vis-à-vis public health workforce recommendations from the CDC.
Learning Outline:
- Pre-session self-assessment
- Introduction to genetics and genomics
- Relevance of genetics/genomics to the essential functions of public health
- On-the-job application of public health genomics
- Post-session self-assessment
Pre-Session Self-Assessment
How prepared are you to use the power of genomics in the work of public health? Fill out the Self-Assessment before going to the next section. If you are using Windows 10 you will need to be sure to right click and open the file in a PDF reader.
Next, work through the “Tour of Basic Genetics” on this page: http://learn.genetics.utah.edu/content/basics/
The term “genetics” typically refers to the study of single genes. New technology now allows relatively quick and increasingly cheaper analysis of multiple genes, even a look at all ~21,000 genes. The study of all of a person’s genetic information, in aggregate, is called “genomics”. Read this overview of genomics from Healthy People 2020 and how it relates to two HP2020 objectives.
Below are some key words and concepts to help you form a knowledge base for public health genomics.
Key Words
- Autosomal dominant– disorders that can occur when only one gene copy (from either parent) has a mutation (e.g. neurofibromatosis, Huntington disease, many cancer susceptibility genes like BRCA1/2)
- Autosomal recessive – disorders that occur only when both gene copies (from each parent) have mutations (e.g. sickle cell anemia, cystic fibrosis)
- Biobank – sometimes called biorepositories; a storage facility, like a library, for biospecimens which may be used for future research
- Epigenetics – the study of biological mechanisms that change gene expression without changing the DNA sequence; epigenetic changes are maintained through cell division from parent to daughter cells.
- Genetics - the scientific study of heredity, how particular qualities or traits are transmitted from parents to offspring.
- Genomics – the study of all of a person’s genes and their function, in aggregate
- Human Genome Project – the 13-year (1990-2003) federal project to map the total human DNA sequence
- Lynch Syndrome – the most common form of hereditary colon cancer, inherited in an autosomal dominant manner. About 2% of colon cancers are associated with Lynch Syndrome.
- Microsatellite instability – within an individual, variation in the lengths of repeated sections of DNA; often a sign that someone’s DNA repair mechanisms are not working properly; commonly found in colon and endometrial cancers associated with Lynch Syndrome
- Mucopolysaccharidosis type 1 (MPS 1) – an autosomal recessive lysosomal storage disease that affects multiple body systems due to deficiency of alpha-L-iduronidase enzye encoded by the IDUA gene.
- Multifactorial – caused by a combination of multiple genetic and environmental factors
- Polymorphism – DNA variation that is not yet known to have clinical significance; polymorphisms are common, sometimes defined as occurring with a frequency of at least 1% in the population.
Concepts:
- It is estimated that influences on health and disease are 40% behavioral, 30% genetic, 20% environmental, and 10% health care.
- The human body contains ~21,000 genes typically packaged for cell division in 46 chromosomes (23 chromosome pairs).
- Genes help determine our responsiveness to environmental changes. Genes also interact with one another.
- The causes of birth defects include chromosomal alterations, DNA changes, teratogens, and multifactorial conditions.
- 3-4% of children are born with a birth defect.
- About 240,000 children in Virginia are estimated to have special health care needs.
- The burden of disease may be reduced through genetic understanding and services.
- Family history is increasingly being valued as a public health tool to screen for common diseases.
- “We are all diseased, just not diagnosed yet.” Francis Collins MD PhD, Medical Geneticist, former Director, National Institute for Human Genome Research, now NIH director
The following web sites may be useful for your further study.
Also, scan the following:
Relevance to the Essential Functions of Public Health
Throughout your training in public health, you will learn about the 10 Essential Public Health Services:
- Monitor health status to identify and solve community health problems.
- Diagnose and investigate health problems and health hazards in the community.
- Inform, educate, and empower people about health issues.
- Mobilize community partnerships and action to identify and solve health problems.
- Develop policies and plans that support individual and community health efforts.
- Enforce laws and regulations that protect health and ensure safety.
- Link people to needed personal health services and assure the provision of health care when otherwise unavailable.
- Assure competent public and personal health care workforce.
- Evaluate effectiveness, accessibility, and quality of personal and population-based health services.
- Research for new insights and innovative solutions to health problems.
An ongoing challenge for public health personnel is to incorporate current understanding of the science of health and disease in effective and ethical public health measures. Your understanding of the relevance of the genetic components of your family health history to your own health, and your willingness to think about these complex issues for society and public health are both part of your legacy. Think genetically.
Review the CDC Genomic Workforce Competencies and continue to reflect upon them as you go through your MPH program.
The following have been identified as public health functions especially relevant to genetics:
- public health assessment
- evaluation of genetic testing
- development, implementation, and evaluation of population interventions; and
- communication and information dissemination.
Critical issues include:
- partnerships and coordination
- ethical, legal and social issues; and
- education and training.
On-the-Job Application of Public Health Genomics
Imagine you have graduated with your MPH. It is your first week as Director of Public Health Genetics for Virginia. This class is going to walk you through three public health genetic issues that arrive on your desk that first week. How will you handle them?
(Each of the PowerPoint presentations below includes audio of the lecturers guiding you through each slide. Make sure you are at a computer at which you can listen to this audio. You will need to manually advance each PowerPoint slide.)
Day #1 as Director of Public Health Genetics
Genetics Competency Elements:
- Identify ethical and medical limitations to genetic testing, including uses that do not benefit the individual.
- Participate in strategic policy planning and development related to genetic testing or genomic programs.
- Participate in the evaluation of program effectiveness, accessibility, cost benefit, cost effectiveness and quality of personal and population-based genomic services in public health.
- Maintain up-to-date knowledge on the development of genetic advances and technologies relevant to his/her specialty or field of expertise and learn the uses of genomics as a tool for achieving public health goals related to his/her field or area of practice.
You receive two reports on your desk:
- The first describes the possibility of expanding the state’s newborn screening panel to include Mucopolysaccharidosis type 1 (MPS 1).
- The second shows a shortage of genetics health professionals who have training to care for infants identified with a disorder on newborn screen.
What other information do you want?
Where are the gaps?
What actions do you recommend?
Newborn Screening Ppt
Some additional background:
1) MMWR Sept. 19 2008:Impact of Expanded Newborn Screening — United States, 2006
2) National Birth Defect Prevention Network
3) National Newborn Screening and Genetics Resource Center
4) Virginia Department of Health Newborn Screening Program
Lecture.
Day #2 as Director of Public Health Genetics
Genetics Competency Elements:
- Apply the basic public health sciences, (including behavioral and social sciences, biostatistics, epidemiology, informatics, environmental health) to genomic issues and studies and genetic testing, using the genomic vocabulary to attain the goal of disease prevention
- Identify ethical and medical limitations to genetic testing, including uses that do not benefit the individual
- Maintain up-to-date knowledge on the development of genetic advances and technologies relevant to his/her specialty or field of expertise and learn the uses of genomics as a tool for achieving public health goals related to his/her field or area of practice
- Participate in strategic policy planning and development related to genetic testing or genomic programs
- Collaborate with existing and emerging health agencies and organizations, academic, research, private and commercial enterprises, including genomic-related businesses, agencies and organizations and community partnerships to identify and solve genomic-related problems
- Participate in the evaluation of program effectiveness, accessibility, cost benefit, cost effectiveness and quality of personal and population-based genomic services in public health
- Develop protocols to ensure informed consent and human subject protection in research
The Board of Medical Assistance Services would like to meet with you about a new Medicaid genetics initiative. They would like to establish a biobank and require all new Medicaid enrollees to contribute a blood sample. Linking their genomic information with Medicaid claims data could provide a treasure trove for epidemiologic research.
What other information do you want?
Where are the gaps?
What actions do you recommend?
BIOBANK PRESENTATION
Some additional background:
Biorepositories and Biospecimen Research Branch of the NIH
Muin Khoury presentation on Epigenetics and Public Health, http://www.astho.org/Annual-Meeting-2014/Presentations/Muin-Khoury-Epigenetics-Session/
Epigenetics: Relevance and Implications for Public Health, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4480875/
Hawkins Virani A and Longstaff H. Ethical considerations in biobanks: How a public health ethics perspective sheds new light on old controversies. J Genet Couns 2015; 24:428-432.
Day #3 as Director of Public Health Genetics
Genetics Competency Elements:
- Apply the basic public health sciences, (including behavioral and social sciences, biostatistics, epidemiology, informatics, environmental health) to genomic issues and studies and genetic testing, using the genomic vocabulary to attain the goal of disease prevention
- Identify the role of cultural, social, behavioral, environmental and genetic factors in development of disease, disease prevention, and health promoting behaviors; and their impact on medical service organization and delivery of services to maximize wellness and prevent disease
- Participate in the evaluation of program effectiveness, accessibility, cost benefit, cost effectiveness and quality of personal and population-based genomic services in public health
- Develop protocols to ensure informed consent and human subject protection in research and human subject protection in research
When you get to your office this morning, you see that someone has left a copy of HP2020 on your desk, opened to the page describing the Genomics objectives. The following objective is highlighted: Increase the proportion of persons with newly diagnosed colorectal cancer who receive genetic testing to identify Lynch syndrome (or familial colorectal cancer syndromes). Attached is a post-it note: “What are we going to do about this? Can the Virginia Cancer Registry help?”
See also this JAMA Viewpoint on Family History
What other information do you want?
Where are the gaps?
What actions do you recommend?
PowerPoint on Colorectal Cancer
Some additional background:
Explore these web sites
Post-Session Self-Assessment Be sure to open in a PDF reader and not in Windows if using Windows 10.
Now that you have reviewed the class materials, are you more competent to incorporate genomics into your public health practice? Did your score on the "self-assessment" improve?
