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Sometimes solutions to living with a medical condition, or even the key to a cure, can be found in the genes.
As researchers delve deeper into the human genome, their findings have uncovered practical applications in health care through genetic testing and counseling.
Genetics impacts all areas of medicine and across a person’s lifespan, according to Tahnee Causey, director of the master’s program in genetic counseling at Virginia Commonwealth University. Genetic counseling and testing are most frequently used by adults with possible cancer predispositions, by some women at risk of complications in pregnancy, in some problematic pregnancies, and in children who have autism or delays in reaching developmental milestones, Causey says.
Genetic testing also may be called for when children are born with a congenital anomaly or dysmorphic features. While testing may provide a reason for the condition, it may not necessarily lead to a cure, according to Dr. Hind Al Saif, assistant professor in genetics and an attending physician in clinical genetics and metabolism for VCU Health and the Children’s Hospital of Richmond at VCU.
Most testing samples are acquired through a cheek swab or blood draw. Some health insurance providers cover costs, which can range from hundreds of dollars to thousands, though many do not. Others may cover single-gene tests but will not approve a genetic panel, which involves more than one gene. “We always have challenges with certain insurance companies about the coverage of genetic testing,” Al Saif says.
Genetic testing dates back decades. Causey notes that the first training program in genetics counseling was established in 1969 at Sarah Lawrence College in Bronxville, New York. When Causey entered the field in the mid-1990s, there were only 16 programs nationally. Now, there are 56. “In the last 20 years, we’ve seen an explosion in genetic testing,” she says.
“As of now, they’re trying to just make it as comprehensive as possible,” Al Saif says. She cites testing done in patients with a seizure disorder that may be genetic in nature. There are many genes that can result in seizures, so a comprehensive genetic test would involve thousands of genes, known as a whole exome sequencing.
One of the broadest tests is whole genome sequencing, which goes beyond searching for genes associated with a specific genetic condition or that are not functioning properly. “There are genes [for which] we don’t know the exact function, and we don’t have enough information about them, and we don’t know whether they cause disease or not,” she says.
Accuracy of results depends on the tests; up to 99% in simpler tests, such as those involving only one condition-related gene. Causey notes that in conditions in which all the genes involved have yet to be identified, genetic counselors can help explain the process and what the results may show. “Conditions that may be caused by multiple genes may not be quite as clear-cut,” she says.
It’s a relatively new field, and for most conditions, there are simply no treatments available, according to Al Saif. But testing can be helpful in other ways. For example, if the diagnosis is for a more common genetic disorder, parents can be provided with guidance on other health issues that may also be associated with the disorder, information on future screenings and details on other specialists the person with the disorder may need to see.
“For the most part, as of now, the reason we do some genetic testing is to give the family or the patients a diagnosis or a name on why they have these symptoms and not necessarily a treatment,” she says.
Many hospitals now offer genetic testing for babies in intensive care. “I would say in the future that it could be offered to all patients, if we can’t find an answer from the initial testing,” she says. “And I would say maybe even [further] in the future if the testing is cheaper, it could be offered to all patients even without starting with smaller testing.”
