Exome Sequencing – A New Take on Family History
I have been enthralled with Genome Sequencing for sometime now – and for good reason:
In one case at Children’s Mercy Hospital in Kansas City, doctors expected to have to remove the pancreas from a baby girl with very low blood sugar. Instead, whole genome sequencing showed that treatment was indeed possible by removing just part of the pancreas. THAT spared the girl having to depend permanently on insulin.
My excitement however, recently reached a new level when I learned how Exome Sequencing is impacting medical practices, empowering adult patients’ personal decisions on treatment choices and, ultimately, saving lives.
By way of example, a recent story in The Wall Street Journal, about a baby who had spent his entire short life in the neonatal intensive care unit while physicians tried to work out the cause of his abnormalities.
When the baby’s liver failed, the medical staff warned his parents that the outlook was grim.
Then geneticist Stephen Kingsmore and his team took on the case. Within three days, they sequenced the genomes of the baby and his parents, and identified a rare mutation that was common to the child and both of his parents.
The baby is now at home and healthy.
The point is, of course, that had physicians sent his DNA off for a conventional genomic test, the diagnosis could have taken more than a month — by which time the baby would have probably died.
But what is really impacting for professionals in the Long Term Care field is that sequencing in infants could also someday provide people with a genetic blueprint to carry through life.
That is, the data gathered at birth could be used years later to diagnose disease and help develop personalized medical treatments later in life, with growing recognition that genome sequencing could someday be part of routine testing done on every baby to reveal a wider range of potential medical risks.
Surprisingly, most of our genome does not contain genes, with many sections of DNA not even containing any genes!
Often, what researchers do is sequence only the parts of the genome that contain genes. These parts are called the “exome”, they make up for about 1 percent of the genome and are the fastest way to look for changes that may cause disease.
For people with suspected rare genetic conditions, getting an accurate diagnosis can be a long and frustrating road, as Doctors can find it challenging to match a complicated set of symptoms to the thousands of known genetic conditions. Exome sequencing can help doctors pinpoint the underlying causes of many rare and hard-to-diagnose genetic conditions.
Referring to a research report presented during the American Society of Human Genetics Annual Meeting this past October, Dr. James R. Lupski indicated that “The findings in this report, will forever change the future practice of medicine as a whole”.
A professor of molecular and human genetics, and coauthor of the report, Dr. Lupski stated that “It is just a matter of time before genomics moves up on the physician’s list of things to do and is ordered before formulating a differential diagnosis. It will be the new “family history” that, better yet, will get you both the important variants inherited from each parent AND the new mutations that contribute to disease susceptibility”.
Indeed, Scientia Potentia Est.
An aphorism in Latin usually translated as “Knowledge is Power”