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gene therapy

Alison Frase with Nibs, a carrier of MTM whose descendants provided the basis for the gene therapy study.

Alison Frase with Nibs, a carrier of MTM whose descendants provided the basis for the gene therapy study.

Babies born with X-linked myotubular myopathy (MTM), which affects about one in 50,000 male births, are commonly referred to as “floppy.” They have very weak skeletal muscles, making it difficult to walk or breathe; survival requires intensive support, often including tube feeding and mechanical ventilation. Most children with MTM never reach adulthood.

One of these children, Joshua Frase, succumbed to MTM on Christmas Eve, 2010. The son of former NFL player Paul Frase, he lived to age 15. But his parents, who continue to actively support MTM research, now see a glimmer of hope for children born with the disease today.

A preclinical study on the cover of last week’s Science Translational Medicine, funded in part by the Joshua Frase Foundation, showed dramatic improvements in muscle strength using gene replacement therapy in mouse and dog models of MTM—paving the way for a potential clinical trial. Full story »

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Researchers have silenced the third copy of chromosome 21, at least in a dish. What might this mean for Down syndrome? (Wikimedia Commons)

Researchers have silenced the third copy of chromosome 21, at least in a dish. What might this mean for Down syndrome? (Wikimedia Commons)

Emily Jean Davidson, MD, MPH, is clinical director of the Down Syndrome Program at Boston Children’s Hospital. Walter Kaufmann, MD, and David Stein, PsyD, research co-directors for the Down Syndrome Program, contributed to this post, along with Nicole Baumer, MD, fellow in Neurodevelopmental Disabilities, and Down Syndrome Program Coordinator Angela Lombardo, BA.

Last week, researchers at the University of Massachusetts published a fascinating and important study on Down syndrome in Nature. Lisa Hall, PhD, Jeanne Lawrence, PhD, and their colleagues were able to effectively “shut down” the gene activity of one of the three copies of the 21st chromosome in cells with trisomy 21.

What exactly did they do?  The research team started with skin cells from a man with trisomy 21 that were transformed into induced pluripotent stem cells—cells that act like cells from an embryo and can develop into different cell types. They then took a gene from the X chromosome that is responsible for making sure that only one X chromosome is active in females—the X-inactivation gene—and inserted it in a specific location on chromosome 21. Full story »

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Will Ward at the NSTAR Walk for Boston Children’s Hospital in 2012—his family’s fifth year leading a team to raise funds for the Beggs Laboratory.

This two-part series examines two potential treatment approaches for myotubular myopathy, a genetic disorder that causes muscle weakness from birth.

Sixth-grader William Ward cruises the hallways at school with a thumb-driven power chair and participates in class with the help of a DynaVox speech device. Although born with a rare, muscle-weakening disease called X-linked myotubular myopathy, or MTM, leaving him virtually immobile, he hasn’t given up.

Neither has Alan Beggs, PhD, who directs the Manton Center for Orphan Disease Research at Boston Children’s Hospital, and who has known Will since he was a newborn in intensive care.

“From the very beginning, Alan connected with our family in a very human way,” says Will’s mother, Erin Ward. “In the scientific community, he’s been the bridge and the connector of researchers around the world. That makes him unique.”

Since the 1990s, Beggs has enrolled more than 500 patients with congenital myopathies from all over the world in genetic studies, seeking causes and potential treatments for congenital myopathies—rare, often fatal diseases that weaken children’s skeletal muscles from birth, often requiring them to breathe on a ventilator and to receive food through a gastrostomy tube. Full story »

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Agustín Cáceres, once a virtual "bubble boy," is no longer on infectious disease precautions.

For the Cáceres family of Argentina, it’s a joyous holiday homecoming. Agustín, who received gene therapy at 5½ months of age, journeyed with his family to Boston for a check-up and got a clean bill of health.

Agustín was born with the rare immune-deficiency disorder SCID-X1. More popularly known as “bubble boy” disease, it left him defenseless against infections, unable to make enough T-cells to fight them off. His baptism was the only time his family could come near him, all wearing masks, gloves and gowns. His infancy was spent in isolation with his mother.

Now, at age 2½, Agustín has been cleared to go to nursery school, ride a bus and attend large family gatherings without fear of contracting a life-threatening infection. When we caught up with him, he was chasing and tumbling with his older brother Jeremías while waiting to bid farewell to his care team. Full story »

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David Williams wants to turn cells from Fanconi anemia (FA) patients into stem-like iPS cells. To do that, though, he needs to get the patients' cells to reboot properly. (_rockinfree/Flickr)

About a decade ago, David Williams, MD, set out to solve a problem. The chief of Dana-Farber/Children’s Hospital Cancer Center’s Hematology/Oncology division wanted to treat Fanconi anemia (FA)—a rare, inherited bone marrow failure disease—using gene therapy. In the process, he’d be able to replace patients’ faulty bone marrow cells with ones corrected for the genetic defect that causes FA.

There was one big problem though. “The main bar to attempting gene therapy in FA is that you need to be able to collect a certain number of blood stem cells from a patient in order to be able to give enough corrected cells back,” he says. “In our early clinical trials, we were unable to provide enough corrected stem cells to reverse the bone marrow failure we see in these patients.”

One way around the supply issue would be to create the necessary blood stem cells from FA patients’ own cells by first reprogramming skin cells into what are called induced pluripotent stem (iPS) cells. Using one of several methods, scientist can reboot mature skin cells into an immature, stem cell-like state—essentially turning the cells’ biological clocks back to a time when they could grow into anything the body might need. Full story »

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Brain tumors like the diffuse, light gray one in this MRI do a remarkably good job of hiding from the immune system. A new treatment based on gene therapy could strip their camouflage away. (Filip Em/Wikimedia Commons)

If there’s anything that tumors are good at, it’s hiding themselves. Not from things like MRIs or CT scans, mind you, but from the immune system. Since a tumor grows from what were at one time normal, healthy cells it’s still “self,” still one of the tissues that makes you you.

“Tumor cells display very subtle differences that distinguish them from healthy cells, but by and large they look the same to your immune system,” says Mark Kieran, a pediatric neuro-oncologist at the Dana-Farber/Children’s Hospital Cancer Center and Children’s Hospital’s Vascular Biology Program. “The question is: How can we unmask tumors so that the immune system can do its job?”

Researchers have worked for years on cancer vaccines aimed at getting the immune system to wake up to the presence of a tumor and turn on it. With a Phase 1 safety trial , Kieran and his colleagues, including Children’s neurosurgical oncologist Lily Goumnerova, are evaluating a different strategy for patients with hard-to-treat brain tumors called malignant gliomas:  They’re giving the tumors a cold. Full story »

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(Molly G. Willikers/Flickr)

Sound waves produce the sensation of hearing by vibrating hair-like structures on the inner ear’s sensory hair cells. But how this mechanical motion gets converted into electrical signals that go to our brains has long been a mystery.

Scientists have believed some undiscovered protein is involved. Such proteins have been identified for taste, smell and sight, but the protein required for hearing has been elusive. In part, that’s because it’s hard to get enough cells from the inner ear to study – they’re embedded deep in the cochlea.

“People have been looking for more than 30 years,” says Jeffrey Holt of the department of otolaryngology at Children’s Hospital Boston. “Five or six possibilities have come up, but didn’t pan out.”

Last week, in the Journal of Clinical Investigation, team led by Holt and Andrew Griffith, of the National Institute on Deafness and Other Communication Disorders (NIDCD), demonstrated that two related proteins, TMC1 and TMC2, are essential for normal hearing – paving the way for a test of gene therapy to reverse a type of genetic deafness.  Full story »

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Within days of injecting a cell mix into mice, numerous blood vessels form. Can these vessels be made to secrete drugs, without the need for IVs or injections?

People who rely on protein-based drugs often have to endure IV hookups or frequent injections, sometimes several times a week. And protein drugs – like Factor VIII and Factor IX for patients with hemophilia, alpha interferon for hepatitis C, interferon beta for multiple sclerosis — are very expensive.

What if they could be made by people’s own bodies?

Combining tissue engineering with gene therapy, researchers at Children’s Hospital Boston showed that it’s possible to get blood vessels, made from genetically engineered cells, to secrete drugs on demand directly into the bloodstream. They proved the concept recently in the journal Blood, reversing anemia in mice with engineered vessels secreting erythropoietin (EPO).

This technology could potentially deliver other protein drugs, Full story »

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The first U.S.-treated patient with his parents. Photo: Patrick Bibbins

Until this month, Agustín Cáceres’s baptism was the only time his family could come close to him. Everyone had to wear masks, gloves and gowns.

After that, he went into isolation, along with his mother Marcela, who came out only for meals. His father Alberto, and his four-year-old brother Jeremías, kept to a separate bedroom. Jeremías had to stop attending nursery school, for fear he’d bring home an infection his baby brother might catch. When Agustín’s relatives came to help out, they had to change their clothes and wash their hands, and couldn’t enter Agustín’s room.

Agustín, born in Argentina, has a form of X-linked Severe Combined Immunodeficiency, or SCID-X1, better known as “bubble boy disease.” Full story »

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A healthy copy of the affected gene is introduced into the patient's stem cells by means of a vector, a genetically altered virus that does not cause ongoing infection. The stem cells, corrected for the defect, are infused back into the patient. (Click to enlarge.)

Gene therapy, still experimental but beginning to enter the clinic, attempts to utilize advanced molecular methods to treat and even reverse genetic diseases. The field started in earnest about 25 years ago and has had many setbacks along the way to its recent earliest successes.

International collaboration has been critical. Children’s Hospital Boston is one of the founding members of the Transatlantic Gene Therapy Consortium (TAGTC), a new collaboration that seeks to facilitate a more rapid advancement of this technology for treating human diseases. It was initiated shortly after the first trials of gene therapy for X-linked Severe Combined Immunodeficiency (X-SCID) (in both Paris and London) reported leukemia as a serious side effect. The TAGTC was formed to address this setback, developing safer gene therapy reagents, sharing the costs of their development, and then implementing new gene therapy trials for rare diseases across multiple international sites. Full story »

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