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The
Human Genome
Genetic Screening
Joann Bodurtha, MD, MPH
Joann Bodurtha, MD, MPH
This column provides a brief overview of some current issues in genetic screening. Subsequent columns will address specific issues of genetic testing in more detail.
“Can’t we just do the genetic screening?”
Currently, screening for genetic conditions rarely uses genetic tests (if one uses that term to mean tests based on DNA or chromosome material). Genetic tests are more commonly used for diagnosis. Some have argued that doctors should stop using the term “genetic screening” and use the more general term “medical screening” or incorporate the more specific disease entity, eg, cystic fibrosis screening, when actually using a DNA test.
Newborn screening for conditions such as phenylketonuria (PKU) and other metabolic conditions provided the model for current genetic screening. For more than 30 years, states have evolved systems to study available testing for newborns, evaluate the impact of testing on disease prevention as well as the benefits, costs, and effectiveness of such programs. Many states have added screening for other metabolic conditions, such as hypothyroidism, where early treatment optimizes health and prevents mental retardation. Screening for hemoglobinopathies such as sickle cell disease, has also increased as data about the effectiveness of early antibiotic prophylaxis reducing death became available. Most recently, states are implementing newborn hearing screening to ensure early communication barriers can be addressed in young children.
National discussion about the addition of more screening tests to newborn screening programs addresses the challenges of competing public health and other budget priorities, individual condition advocacy, relative lack of health literacy, and gaps in capacity to intervene effectively in some conditions. One of the legacy concerns for current practitioners is realizing that women who had conditions such as PKU, galactosemia, congenital adrenal hyperplasia, and sickle cell disease identified on newborn screening a generation ago need more specific adult health care management, especially in pregnancy.
Prenatal genetic screening often is considered to include a broad range of items—from the American College of Obstetrics and Gynecology (ACOG) checklist for family history to maternal serum screening for Down syndrome and neural tube defects, as well as the new ACOG and American College of Medical Genetics recommendation that cystic fibrosis carrier screening be offered to all couples considering pregnancy or who are pregnant. Unfortunately, many women still do not recognize these are in fact screening tests, not diagnostic tests, and may not make informed choices about having or not having these tests. The challenges of communicating information about this growing array of tests and providing appropriate informed consent may be addressed by working collaboratively with genetic counselors who can not only provide individual genetic counseling but help develop triage and referral systems with OB/GYNs and family practitioners.
Workplace screening has the potential to help employees minimize illness but is generally not considered cost effective and raises many privacy and discrimination issues. Evolving legal concerns, ranging from what is actually covered in the Americans with Disabilities Act to who is liable for cancer related to life-long smoking exposure, complicate the already tangled web of health insurance coverage. Some states have passed laws barring discrimination in health insurance based on genetic susceptibility testing, but these issues are far from settled.
As a result of the Human Genome Project, genetic tests for determining an individual’s risk of disease are becoming increasingly available. Educational materials have been developed by companies holding patents on such tests, by professional organizations, and by patient advocacy groups. Some resources for keeping informed about genetic screening tests so that you may best care for your patients are listed in the Table.
Table. Resources |
www.acmg.net (The American College of Medical Genetics, the professional
organization of medical geneticists)www. ACOG.org/publicsearch (ACOG
Resource Center–202-863-2528 for up to five ACOG patient education
pamphlets, fax request 202-484-1595)
www.faseb.org/genetics/ashg (The American Society of Human Genetics,
a professional organization including geneticists who address policy
issues in genetics)
www.geneticalliance.org (The Genetic Alliance, an umbrella organization
of hundreds of genetic condition organizations)
www.geneclinics.org (a public resource with peer-reviewed summaries
of genetic conditions including current testing and a laboratory resource
directory)
www.genome.gov (provides access to multiple links relating to the Human
Genome Project and activities of the National Human Genome Research Institute)
www.nsgc.gov (The National Society of Genetic Counselors, the professional
organization of genetic counselors) |
Joann Bodurtha, MD, MPH, is professor of human genetics, pediatrics, and obstetrics-gynecology at Virginia Commonwealth University in Richmond.
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