What is the difference between (human) genetics and genomics?

Genetics is the study of inheritance, or the way traits are passed down from one generation to another.  Genes carry the instructions for making proteins, which in turn direct the activities of cells and functions of the body that influence traits such as hair and eye color.  Genomics is a newer term that describes the study of all the genes in a person, as well as interactions of those genes with each other and with that person's environment.  From a public health perspective, it is hoped that genomics will enhance our understanding of health and disease.

Public Health Genomics

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What are genetic disorders?

Genetic disorders are inherited medical conditions caused by abnormalities in a specific gene or chromosome.

Genetic disorders can be grouped into the following categories:

  1. Single gene disorders result when a mutation causes a protein product of a single gene to be altered or missing.  Examples include cystic fibrosis, sickle cell anemia, and Huntington's disease.

  2. Chromosome abnormalities result when entire chromosomes, or large segments of them, are missing, duplicated, or otherwise altered.  For example, Down syndrome is a disorder that occurs when a person has three copies of chromosome 21.

  3. Mitochondrial disorders are relatively rare disorders caused by DNA mutations of mitochondria, which are small organelles involved in cellular respiration and which are located in a cell's cytoplasm.  Examples include an eye disease called Leber's hereditary optic atrophy and a type of epilepsy known as Myoclonus Epilepsy with Ragged Red Fibers (MERRF).

  4. Multifactorial disorders are those conditions presumed to result from involvement of multiple genes, often in combination with environmental components.  Examples include asthma, heart disease, diabetes, most cancers, arthritis, and Alzheimer's disease.

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How do I find more information about a specific genetic disorder?

Online resources are available that provide information about numerous genetic disorders:

  • GeneReviews, a product of the National Center for Biotechnology Information, is a collection of disease descriptions that relate genetic testing to the diagnosis, management, and genetic counseling of individuals and families with specific inherited disorders. This resource is peer-reviewed and routinely updated.

  • Genetic and Rare Conditions Site, from the University of Kansas Medical Center, provides a searchable alphabetical index of genetic disorders.

  • Genetics Home Reference is a service of the National Library of Medicine that provides consumer information about genetic conditions and Newborn Screening.

  • National Organization for Rare Disorders (NORD) is supported by more than 230 patient organizations serving people with rare disorders (i.e., affecting fewer than 200,000 people in the U.S.). NORD maintains a database of more than 1,200 disorders.

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What are genetic services?

Genetic services include genetic testing, diagnosis of genetic conditions, genetic counseling and support for individuals and families, and treatments for individuals with genetic disorders.

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What is genetic testing?

Genetic testing refers to the laboratory analysis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), chromosomes, or gene products (e.g., proteins) that provides specific information about inherited variations in genes or chromosomes of an individual. Genetic testing is used to diagnose and manage disease, predict the risk of future disease, and inform decisions about life planning. 

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What are genetic counselors and what do they do?

Genetic counselors are trained healthcare professionals who provide information and support to individuals and families who have members with a genetic disorder or birth defect.  They also provide services to families who may be at risk for developing a genetic disorder or who are concerned that they may have a child with an inherited disease.

As the field of genetics has expanded, genetic counselors have grown more specialized.  They may deal with a specific disease (such as breast cancer), a certain age group (such as adolescents), or a particular type of counseling (such as prenatal).

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How can I find a genetic counselor?

One place to begin your search is with your own doctor, who may directly refer you to a genetic counselor. In addition, university genetics departments and medical centers often have affiliated genetic counselors, or can provide referrals to a counselor or genetics clinic.

The National Society of Genetic Counselors provides an online lookup tool, Find a Genetic Counselor.

Genetic Centers, Clinics, and Departments, from the University of Kansas Medical Center, provides a comprehensive resource list for genetic counseling, including links to the American Board of Genetic Counseling.

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What is the Connecticut Newborn Screening Program?

The Connecticut Newborn Screening Program includes: laboratory screening, hearing screening, and birth defects screening. CT State Law mandates that each institution that provides childbirth services, shall implement a universal newborn laboratory, hearing and birth defects screening program as part of its standard of care. The screening program assures identification of newborns at risk and prompt referrals to specialty centers for confirmation testing, treatment/intervention and follow up services to promote optimal health and development.

Click the following link for more information about newborn screening.

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What disorders does the Connecticut Laboratory Newborn Screening Program screen for?

In 1964, the CT Statewide Laboratory Newborn Screening Program was started with the screening for phenylketonuria (PKU) and galactosemia. Through the years disorders were added to the screening panel. CT has joined other states by implementing the expanded screening using the Tandem Mass Spectrometry Instrument. Currently, Connecticut newborns are screened for 40 disorders. The goal of newborn screening is early identification of infants at increased risk for selected metabolic or genetic disorders, so that medical treatment can be promptly initiated to avert complications and prevent irreversible problems. Over 1.8 million newborns have been tested since the program began.

Click the following link for more information about newborn screening.

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What is the Human Genome Project?

The Human Genome Project was an international research effort formally begun in October 1990 to determine the complete chemical sequence of the 3 billion base pairs of human DNA and to identify all of the genes in the human genome.  The project was considered completed in 2003 and the number of protein-encoding genes was found to be in the range of 20,000-25,000.

The Department of Energy Human Genome Program and the National Human Genome Research Institute (NHGRI) of the National Institutes of Health together sponsored the U.S. Human Genome Project.

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What is GINA?

GINA is the first piece of federal legislation to provide protections against discrimination in health insurance coverage and employment settings based on an individual’s genetic information .

Specifically, the legislation protects against genetic discrimination by health insurers or employers by:
  • Prohibiting group health insurance plans and issuers offering coverage on the group or individual market from basing eligibility determinations or adjusting premiums or contributions on the basis of an individual’s genetic information. Insurance companies cannot request, require, or purchase the results of genetic tests, and they are prohibited from disclosing personal genetic information.
  • Prohibiting issuers of Medigap policies from adjusting pricing or conditioning eligibility on the basis of genetic information. They cannot request, require, or purchase the results of genetic tests, or disclose genetic information.
  • Prohibiting employers from firing, refusing to hire, or otherwise discriminating with respect to compensation, terms, conditions, or privileges of employment.  Employers may not request, require, or purchase genetic information, and they are also prohibited from disclosing personal genetic information. Similar provisions apply to employment agencies and labor organizations. 
For more information, please go to the Genomics Resources & Links web page. 

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