Baylor College of Medicine

BCM launches Whole Exome Sequencing Clinical Test

Glenna Picton


Houston, TX -

The newly launched Whole Genome Laboratory (WGL) at Baylor College of Medicine applies the power of next-generation DNA sequencing technology to unanswered genetic questions that directly affect patients' health.

The Whole Genome Laboratory is a joint project of the BCM Human Genome Sequencing Center, the BCM Department of Molecular and Human Genetics and the Medical Genetics Laboratories of BCM. It introduces a new paradigm in genetic testing that promises to supersede current procedures limited to known mutations in a gene or panel of genes.

The laboratory not only makes available the advances of high tech DNA sequencing, it also provides the interpretation by trained clinical genetics experts who will transmit the findings to a referring physician.

"For decades, we have seen patients with various genetic conditions including intellectual disability, autism, epilepsy, birth defects and many others, but often we have been unable to identify the abnormal gene. Now by sequencing the exome of these patients, we will have for the first time the potential to identify the abnormal gene in the majority of cases. Identifying the gene involved is the necessary first step in the path to developing meaningful treatment and prevention," said Dr. Arthur Beaudet, chair and professor of molecular and human genetics at BCM.

The first test to be provided by the by WGL is the Whole Exome Sequencing test. The test will cost about $9,000, although it is anticipated that the price will decrease as technology improves and experience grows.

"The Baylor Human Genome Sequencing Center pioneered exome capture sequencing and the WGL takes advantage of this deep experience. This launch of whole exome sequencing is an ultimate translational benefit of decades of HGSC research," said Dr. Richard Gibbs, director of the Baylor Human Genome Sequencing Center.

"Exome sequencing has the potential to change the way we identify the genetic mutations of and care for our most challenging patients. The Baylor team's experience in genome sequencing, clinical interpretation of genetic test results, clinical genetics and genetic counseling makes us uniquely suited to translate this technology to routine patient care,"said Dr. Christine Eng, professor of molecular and human genetics and director of the dna diagnostic laboratory in the Medical Genetics Laboratory at Baylor.

"We have estimated that 25 percent of the patients in the Blue Bird Clinic for Pediatric Neurology at Texas Children's Hospital have a genetic disorder that is either not previously described or does not have a discovered genetic basis," said Dr. Gary D. Clark, chief of the neurology service at Texas Children's Hospital and a professor of pediatrics, neurology and neuroscience at BCM. "Whole exome sequencing in our clinic population has led and will lead to new discoveries. Further, this technology will assist our patients and their families in understanding the cause of neurologic disease and the risk of recurrence. We believe that whole exome sequencing represents the next revolution in genetic testing and are eagerly embracing this technology."

The procedure begins when a physician requests that patient have the Whole Exome Sequencing test from the Whole Genome Laboratory. Often, this occurs in children when medical history and symptoms point to a genetic disease but the gene mutation has not yet been identified. Patients may have undergone other genetic testing previously, but the problem gene could not be found as costs mount, said Beaudet.

In this case, the Whole Genome Laboratory personnel extract DNA from a blood or other tissue sample obtained from the patient and, using high throughput sequencing machines, determine the genetic code of the sample, testing and retesting to assure accuracy. Sometimes, the test will also involve DNA taken from parents for comparison.

A trained clinical geneticist will evaluate the results of the Whole Exome Sequencing to identify known or predicted deleterious mutations in genes associated with human disorders, said Beaudet. That information will go to the referring physician, who then communicates it to the patient or parents. If other findings that have a medical significance come up, those will also be communicated to the physician, who will then inform the parents or patients.

For more information on or to request the test, please contact T. Brandon Perthuis, Director, Business Development, Medical Genetics Laboratory, office (713) 798-5767 or fax (713) 798-4187. His email is

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