Stanford University School of Medicine researchers have designed a faster, cheaper, more accurate test for identifying genetic defects in heart patients that will shorten the time to diagnose unusual or difficult cases of heart disease.
If you or a loved one in Pacific Grove are experiencing a difficult case of cardiac disease to pin down, their new technique could eventually allow physicians to diagnose genetic heart diseases by rapidly scanning the more than 85 genes recognized for causing cardiac anomalies.
A majority of heart disease cases are due to a lifetime of smoking cigarettes, consuming trans fats and high glycemic meals. However, a subgroup of heart patients has their illness due cardiac anomalies that may be caused by genetic defects. A new, streamlined genetic test that may be able to pinpoint the likely genetic causes of cardiac disease has been developed by Joseph Wu, MD, Ph.D., professor of cardiovascular medicine and radiology, and Kitchener Wilson, MD, Ph.D., instructor of pathology, teamed with a group of genome-sequencing specialists.
Rather than attempt a full genome sequencing involving thousands of genes, taking weeks or months for results, and costing $1,000 or more, Wilson and Wu’s team looked at only the 88 genes known to have mutations that cause cardiac problems. The new test costs $100 for materials, and the results are available within three days.
To survey a small subgroup of relevant genes instead of the whole genome is an approach already in use for tests for cystic fibrosis that involve one gene with hundreds of variants. Wilson said that heart diseases, in comparison, are more challenging because there are so many genes to sequence. Doing that accurately has been difficult and, up to now, too expensive for most labs, he said.
This genetic testing isn’t for the typical, older cardiac patient who comes in with chest pain, resulting from a lifetime of poor diet and infrequent exercise. Such patients can be treated with surgical interventions. Wu, director of Stanford’s Cardiovascular Institute, said that if a 30-year-old woman comes in with chest pain and her doctors are unable to find any obvious reason she should be having heart problems at that young an age, it could be the time for doctors to bring out the complementary long padlock probes, or cLPPs, for inherited cardiac disease.
CLPPs are simple probes, developed at the Stanford Genome Technology Center, that accurately target specific parts of the genome, and that can be made at low cost in large batches. They are easily customized to target different genes because of their simplicity. Wilson and Wu spearheaded the effort to apply cLPPs to diagnosing cardiac diseases.
The researchers said that a preliminary test of the streamlined genetic test or assay on twenty-nine participants from families with inherited heart disease showed that the heart disease cLPP assay was faster, cheaper, and more accurate than whole-genome tests, thus validating the cLPP approach.
The team plans to test the technique next on a group of 200-300 patients. In the meantime, Wu and Wilson will offer the genetic assay free to any research lab that wants to try it.
The assay will speed up diagnosing unusual or difficult cardiac disease cases, according to Wu. He said that, Suppose a 60-year-old patient comes in with heart failure. They perform the angiogram and discover no history of heart attack or other issues, and yet the heart is not performing well. They also discover that several members of his family have similar heart conditions. If they run the new genetic assay and find a genetic cause, such as dilated cardiomyopathy, for the man’s illness, they now have both a diagnosis and a cause, and they could initiate treatment immediately.
Not having the assay result increases costs and delays diagnosis because you’re going through a whole bunch of tests, Wu added. “Sometimes it becomes a fishing expedition,” he said, “which can be frustrating to both the physician and the patient.” Wu said that the most important benefit, perhaps, was being able to give accurate answers to the patient about his or her disease.
Kitchener Wilson and Joseph Wu said the genome technology group had been working on the cLPP technique for a long time. Wilson said, “Our goal is to make genetic testing more accessible to more people.” He added, “We want to democratize it.” Wilson and Wu, for now, are releasing the genetic assay free of charge: Researchers can get samples of the assay to run it themselves. They are also releasing all of the technical data for the complementary long padlock probes so researchers can recreate and modify the probes.
The new test is an example of precision health, enabling researchers and physicians to develop approaches to early detection and prevention, better predict individual risks for specific diseases, and help clinicians make decisions in real-time about how best to care for patients. At California Coastal Homes, we hope that advances such as this can help cardiac afflicted residents gain treatment so that, once again, they can enjoy their Pacific Grove surroundings with peace of mind.