Analyzing blood samples, researchers have found that over one third of chronic kidney diseases are caused by single mutations on single genes
(Image: Graham Colm)
Part 2 of a two-part series on kidney disease. Part 1 is here.
Friedhelm Hildebrandt, MD, receives around one blood sample in the mail per day from a patient with chronic kidney disease. Over 10 years, he’s collected more than 5,000 samples from patients all over the world—in hopes of finding the genetic mutations that cause them and, ultimately, new treatments.
Consider the mutation in an 8-month-old boy from Turkey, who had fluid collection under his skin and elevated protein in his urine—signs that his kidneys were failing. Doctors identified his disease as a form of nephrotic syndrome, one of the three main types of chronic kidney disease. The disease was proving to be hard to treat: Ten weeks of steroids had produced no result, and an immunosuppressant hadn’t been effective enough to justify its harsh side effects.
Only within the last year, genetic research has revealed that more than 30 percent of childhood chronic kidney diseases—like this child’s—stem from single mutations in single genes.
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Liam Burns died 12 days after birth from an unexplained set of heart defects. His parents hope the CLARITY challenge will provide a meaningful explanation.
One extended family has a range of unexplained heart defects—sometimes a hole in the heart, sometimes an arrhythmia. One child, Liam Burns, died days after birth from an underdeveloped heart, a narrowed artery to the lungs and an electrical block. Yet other family members have little more than a heart murmur. All of the defects are on the right side of the heart.
Another family’s son, 11-year-old Adam Foye, has unexplained muscle weakness and fatigue. He can walk only short distances and needs a ventilator at night to support his breathing.
These families—and a third that chose to remain anonymous—decided to submit their DNA to a challenge sponsored by Boston Children’s Hospital called CLARITY. Not only have their complete genomes been sequenced, but 30 teams all over the world—from biotech startups to the National Institutes of Health—were given access to the sequences and set loose to come up with “best practices” for interpreting the results. Two dozen turned in submissions, now being evaluated by a panel of judges. Full story »
Mary Elizabeth Stone and her son John, with genetic counselor Meghan Connolly and Pankaj Agrawal, principal investigator of the Gene Discovery Core. (Courtesy ME Stone)
Sequencing a patient’s genome to figure out the exact source of his or her disease isn’t standard operating procedure — yet. But falling sequencing costs and a growing number of successes are starting to bring this approach into the mainstream, helping patients and families while advancing a broader understanding of their diseases.
The Stone family is a case in point. When John and Warren Stone were born, their parents were envisioning life raising identical twins, when suddenly everything changed. On their second day of life, the twins started to have seizures with stiffening of their arms and legs; more alarmingly, they would stop breathing from time to time, requiring a ventilator to help them breathe. Further work-up revealed that both John and Warren were having persistent seizures consistent with Ohtahara syndrome, a rare, debilitating seizure disorder.
Warren died a few weeks later, and the family transferred John’s care to Boston Children’s Hospital. An extensive clinical and genetic work-up here and at several other hospitals involved in his care — including sequencing all the genes known to cause Ohtahara syndrome – identified no cause for John’s unique seizures. Full story »
(Karl-Ludwig Poggemann/Wikimedia Commons)
Recently, in the hospital cafeteria, I overheard a group of researchers discussing the upcoming availability of whole-genome sequencing to physicians. “We should devise a way to study how physicians will use this,” said one of them—underscoring the disruptive nature of the transformation that is currently happening in medicine.
The ability to immediately obtain whole-genome sequences from patients holds enormous potential for understanding and treating human disease. The list of studies reporting successful diagnosis of otherwise elusive orphan conditions is already too long to recount—more than 600 articles in PubMed as of the date of this posting—including poignant examples of advancing clinical care. Full story »
