Rare diseases offer a lot of opportunity for gene discovery, but getting a drug to market presents many challenges, and costs per patient are high. This 50-minute session explored this complicated landscape from multiple angles. The panelists:
Jay Berry, MD, MPH, is a pediatrician and hospitalist in the Complex Care Service at Boston Children’s Hospital.
Growing up, my parents repeatedly reminded me that “money doesn’t grow on trees.” They pleaded with me to spend it wisely. I’ve recently been thinking a lot about my parents and how their advice might apply to health care spending for my patients.
As a general pediatrician with the Complex Care Service at Boston Children’s Hospital, I care for “medically complex” children. These children—numbering an estimated 500,000 in the U.S.— have serious chronic health problems such as severe cerebral palsy and Pompe disease. Many of them rely on medical technology, like feeding and breathing tubes, to help maintain their health.
These children are expensive to take care of. They make frequent health care visits and tend be high utilizers of medications and equipment. Some use the emergency department and the hospital so often that they’ve been dubbed frequent flyers.
The fact that childhood cancer is, thankfully, rare belies the fact that it is the leading cause of disease-related death in U.S. children age 1 to 19. The number of people with a direct stake in expanding research into pediatric cancer is quite large, well beyond the small number of children with cancer and their families. Not only are the life-long contributions of children cured of cancer enormous, but understanding cancers of young children could also hold the key to understanding a broad range of adult cancers. The time is ripe to allocate more resources, public and private, to research on pediatric cancer.
In an age of increased understanding of the genetic basis of diseases, one thing is striking about many childhood cancers. They are relatively “quiet” cancers, with very few mutations of the DNA. Young children haven’t lived long enough to acquire the large number of mutations that create the background “noise” associated with years of living. This makes it much easier to pinpoint the relevant genetic abnormalities in a young child’s cancer.
Add to this the growing realization that biology, including how various tumors use common “pathways,” is a major factor in how the cancer responds to treatment. Thus, a mechanism that’s relatively easier to observe in the cancers of young children could help scientists understand cancers in adults, in whom the same mechanism is hidden amid the clutter of mutations acquired over a longer life.
Saltonstall spoke today with five other panelists at Boston Children’s Hospital’s Global Pediatric Innovation Summit + Awards in a session titled, “Rare diseases: Lessons from the path less chosen.” David Meeker, MD, president and CEO of Genzyme, moderated.
Vector took a moment this morning at the Boston Children’s Hospital Global Pediatric Innovation Summit + Awards to catch up with the Gene Discovery Core at the Manton Center for Orphan Disease Research. Its exhibition table doesn’t have fancy mannequins or flashy screens, but this team is rocking genetics and genomics, one patient at a time.
The usual methods for finding disease-causing genes don’t work for many patients who walk in the doors of Boston Children’s, or who mail in samples from all over the world. They may be one of just a handful of patients in the world with their condition—which may not even have a name yet.
In the world of fatal congenital immunodeficiency diseases, good news is always welcome, because most patients die before their first birthday if not treated. Babies with severe combined immunodeficiency disease, aka SCID or the “bubble boy disease,” now have more hope for survival thanks to two pieces of good news.
Nephrotic syndrome is one of the worst diseases a child can have. It strikes the filtering units of the kidney, structures known as glomeruli. There’s no good treatment: Steroids are the main therapy used, but 20 percent of cases are steroid-resistant. In the syndrome’s most severe form, focal segmental glomerulosclerosis (FSGS), children are forced onto chronic dialysis and often require a kidney transplant—often only to have their disease recur in the new organ.
It’s become clear that our DNA is far from identical from cell to cell and that disease-causing mutations can happen in some of our cells and not others, arising at some point after we’re conceived. These so-called somatic mutations—affecting just a percentage of cells—are subtle and easy to overlook, even with next-generation genomic sequencing. And they could be more important in neurologic and psychiatric disorders than we thought.
“There are two kinds of somatic mutations that get missed,” says Christopher Walsh, MD, PhD, chief of Genetics and Genomics at Boston Children’s Hospital. “One is mutations that are limited to specific tissues: If we do a blood test, but the mutation is only in the brain, we won’t find it. Other mutations may be in all tissues but in only a fraction of the cells—a mosaic pattern. These could be detectable through a blood test in the clinic but aren’t common enough to be easily detectable.”
That’s where deep sequencing comes in. Reporting last month in The New England Journal of Medicine, Walsh and postdoctoral fellow Saumya Jamuar, MD, used the technique in 158 patients with brain malformations of unknown genetic cause, some from Walsh’s clinic, who had symptoms such as seizures, intellectual disability and speech and language impairments.
At first, Corrie and Adam Mendes thought their daughter Emmie had an inner ear problem. She was late with several early milestones, including walking, and when she did walk, she often lost her balance. The family pediatrician sent them to a neurologist, who ordered a brain MRI and diagnosed her with pachygyria, a rare condition in which the brain is smoother than normal, lacking its usual number of folds.
Additionally, Emmie’s ventricles, the fluid-filled cushions around the brain, looked enlarged, so the neurologist recommended brain surgery to install a shunt to drain off fluid. He advised Corrie and Adam that Emmie’s life expectancy would be greatly reduced.
Inflammatory bowel disease (IBD) is miserable for anyone, but when it strikes a child under age 5, it’s much more severe, usually causing bloody diarrhea, wrenching abdominal pain and stunted growth. Early-onset IBD is rare, but on the rise: For reasons unknown, its incidence is increasing by about 5 percent per year in some parts of the world.
A recently identified form of early-onset IBD shows up within months of birth, causing severe inflammation in the large intestine and abscesses around the anus. Recently linked to genetic mutations in the cellular receptor for a signaling protein, interleukin-10 (IL-10), it can also lead to lymphoma later in life.
As with all early-onset IBD, IL-10-receptor deficiency has no good treatment. A bone marrow transplant is actually curative, but carries many risks, especially in infants.
“We’ve been trying to understand why IBD in these children is so severe and presents so early,” says Dror Shouval, MD, a pediatric gastroenterologist at Boston Children’s Hospital and a fellow in the lab of Scott Snapper, MD, PhD. The beginnings of such an understanding—detailed recently in the journal Immunity—could lead to a new treatment approach for this and perhaps other kinds of early-onset IBD.