From mice to humans: Genetic syndromes may be key to finding autism treatment

Boy and a mouse eye-to-eye
(Aliaksei Lasevich/stock.adobe.com)

A beautiful, happy little girl, Emma is the apple of her parents’ eyes and adored by her older sister. The only aspect of her day that is different from any other 6-month-old’s is the medicine she receives twice a day as part of a clinical trial for tuberous sclerosis complex (TSC).

Emma’s mother was just 20 weeks pregnant when she first heard the words “tuberous sclerosis,” a rare genetic condition that causes tumors to grow in various organs of the body. Prenatal imaging showed multiple benign tumors in Emma’s heart.

Emma displays no symptoms of her disease, except for random “spikes” on her electroencephalogram (EEG) picked up by her doctors at Boston Children’s Hospital. The medication she is receiving is part of the Preventing Epilepsy Using Vigabatrin in Infants with TSC (PREVeNT) trial. Her mother desperately hopes it is the active antiepileptic drug, vigabatrin, rather than placebo.

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Saving Vanessa part 2: Parent-driven science

DADA2 symptoms can be controlled with medications
Why did Vanessa’s mysterious rheumatologic condition cause her to have a stroke?

Two-year-old Vanessa had survived the unthinkable: two massive cerebral hemorrhages, nine days apart. Katherine Bell and her wife Nancy Mendoza felt immense relief at their daughter’s close call. But they wanted to know more. What had caused Vanessa’s strokes? Would there be more? Was the cause treatable?

The strokes were the culmination of a mysterious illness that had started with a rash. Because of high levels of inflammatory proteins in her blood, Vanessa’s rheumatologists, Pui Lee, MD PhD and Robert Sundel, MD, had given her a provisional, somewhat vague diagnosis of periodic fever syndrome.

“In rheumatology, we have to be comfortable with operating with a lot of unknowns,” Lee says.

But the strokes occurred despite three different anti-inflammatory treatments, which worked only temporarily. Bell, less comfortable with the unknowns, began searching the medical literature.

“It helped me feel calmer,” Bell says. “The more information I have, the less out of control I feel.”

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Training neurosurgeons in a rare hydrocephalus procedure, with a little help from Hollywood

ETV trainer

A 4-year-old has a progressively enlarging head and loss of developmental milestones: a clear case of hydrocephalus. He undergoes a minimally invasive endoscopic third ventriculostomy (ETV) to drain off the trapped cerebrospinal fluid.

This requires puncturing the floor of the brain’s third ventricle (fluid-filled cavity) with an endoscope — while avoiding a lethal tear in the basilar artery, which lies perilously close.

There are no good neurosurgical training models for this rare and scary operation.

“We semi-blindly poke a hole through the ventricle floor,” says Benjamin Warf, MD, director of Neonatal and Congenital Anomaly Neurosurgery at Boston Children’s Hospital. “To make the technique safer and to be able to train more people, it would be very helpful to make that hole in a way that’s less anxiety-provoking.”

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Severe flu infections linked to underlying genetic variation

Flu virusesThe Center for Disease Control estimates that influenza virus–related illnesses account for more than 200,000 U.S. hospitalizations and 12,000 deaths annually. Young children, the elderly and people with respiratory, cardiac and other chronic health conditions are at particularly high risk for being hospitalized for influenza-related complications. Until now, there has not been a clear reason to explain why some individuals become severely ill from flu and not others.

New findings published in Nature Medicine, however, might change that.

“We’ve identified a genetic variant that we believe may put people at risk of getting life-threatening influenza infections,” says Adrienne Randolph, MD, MSc, a senior associate in pediatric critical care medicine at the Boston Children’s Hospital.

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Newly-discovered epigenetic mechanism switches off genes regulating embryonic and placental development

Artwork depicting DNA and the code of genes

A biological process known as genomic imprinting helps control early mammalian development by turning genes on and off as the embryo and placenta grow. Errors in genomic imprinting can cause severe disorders and profound developmental defects that lead to lifelong health problems, yet the mechanisms behind these critical gene-regulating processes — and the glitches that cause them to go awry — have not been well understood.

Now, scientists at Harvard Medical School (HMS) and Boston Children’s Hospital have identified a mechanism that regulates the imprinting of multiple genes, including some of those critical to placental growth during early embryonic development in mice. The results were reported yesterday in Nature.

“A gene that is turned off by epigenetic modifications can be turned on much more easily than a gene that is mutated or missing can be fixed,” said Yi Zhang, PhD, a senior investigator in the Boston Children’s Program in Molecular and Cellular Medicine, a professor of pediatrics at HMS and a Howard Hughes Medical Institute investigator. “Our discovery sheds new light on a fundamental biological mechanism and can lay the groundwork for therapeutic advances.”

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CRISPR enables cancer immunotherapy drug discovery

Artwork depicting cancer cells with different genes deleted by CRISPR-Cas9, performed to identify novel cancer immunotherapy targets
These cancer cells (colored shapes) each have a different gene deleted through CRISPR-Cas9 technology. In a novel genetic screening approach, the T cells (red) destroy those cancer cells that have lost genes essential for evading immune attack, revealing potential drug targets for enhancing PD-1-checkpoint-based cancer immunotherapy. Credit: Haining Lab 

A novel screening method using CRISPR-Cas9 genome editing technology has revealed new drug targets that could potentially enhance the effectiveness of PD-1 checkpoint inhibitors, a promising new class of cancer immunotherapy.

The method, developed by a team at Dana-Farber/Boston Children’s Cancer and Blood Disorders Center, uses CRISPR-Cas9 to systematically delete thousands of tumor genes to test their function in a mouse model. In findings published today by Nature, researchers led by pediatric oncologist W. Nick Haining, BM, BCh report that deletion of one gene, Ptpn2, made tumor cells more susceptible to PD-1 checkpoint inhibitors. Other novel drug targets are likely around the corner.

PD-1 inhibition “releases the brakes” on immune cells, enabling them to locate and destroy cancer cells. But for many patients, it’s not effective enough on its own.

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Late-breaking mutations may play an important role in autism

somatic mutations in autism may occur at different times in the embryo
Post-zygotic mutations, which arise spontaneously in an embryonic cell after sperm meets egg, are important players in autism spectrum disorder, a large study suggests.

Over the past decade, mutations to more than 60 different genes have been linked with autism spectrum disorder (ASD), including de novo mutations, which occur spontaneously and aren’t inherited. But much of autism still remains unexplained.

A new study of nearly 6,000 families implicates a hard-to-find category of de novo mutations: those that occur after conception, and therefore affect only a subset of cells. Findings were published today in Nature Neuroscience.

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Building precision medicine: Power to the patients

Tools to build precision medicinePrecision medicine involves the development and application of targeted therapeutics based on patients’ genomes, lifestyles and environments. The recent conference on precision medicine at Harvard Medical School highlighted a few challenges in scaling up this process.

To help further precision medicine, the Obama administration and NIH launched the All of Us program, registrations for which are slated to start later this year. Its aim is to collect health data from one million Americans.

But the conference also highlighted several tools that patients can use proactively to collect, share and analyze their own data and use it to improve their own health — and contribute to precision medicine as citizen scientists.

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SIDS associated with higher blood serotonin levels

A baby sleeping on its back, which is the safest sleeping position to prevent SIDS
The Safe to Sleep campaign has helped reduce SIDS deaths, but underlying causes for SIDS have largely remained mysterious.

Sudden infant death syndrome (SIDS) accounts for the greatest share of deaths in children between the ages of 1 and 12 months. What if a blood test could explain a third of SIDS deaths – and in the future, help prevent them? New findings by a Boston Children’s Hospital team show that an increased level of serotonin in blood serum may underpin some SIDS deaths and suggests the possibility that this biological vulnerability may one day be detected in the blood of living infants.

While there are known risk factors for SIDS — such as sleeping face-down or on soft surfaces — how and why such seemingly minor threats kill some children, and not others, remains a mystery.

“Research on the underlying pathology of SIDS is critical to further our understanding of the biological mechanisms contributing to a SIDS death,” says Robin Haynes, PhD, a researcher in the Department of Pathology at Boston Children’s Hospital.

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When you talk to your baby, does his heart rate change? The answer could relate to his autism risk

heart rate autism - NIRS study
The researchers used functional near-infrared spectroscopy (fNIRS), which measures blood oxygen levels in the brain. They then applied their own algorithm to calculate heart rate from the data. (Image courtesy Katherine Perdue)

When infants see or hear something interesting to them, like the sound of a human voice, their heart rate tends to slow down ever so slightly, a sign they’re paying attention. But a recent small study suggests this may not be true for infants at risk for autism.

Researchers led by Katherine Perdue, PhD, of the Laboratories of Cognitive Neuroscience at Boston Children’s Hospital, studied 40 babies who had an older sibling with autism spectrum disorder (ASD). These “baby sibs” are at 20-fold risk for developing autism themselves. For comparison, Perdue and colleagues also studied 48 infants who did not have a sibling with ASD and were therefore at low risk for autism.

At 3, 6, 9 and 12 months of age, the at-risk infants had slower heartbeats than the low-risk infants. When the babies were presented with speech sounds, heart rates slowed less in the at-risk babies than in the low-risk infants.

While none of the at-risk infants, followed until age 2, were later diagnosed with ASD, the researchers believe they may still be at risk for problems such as delayed speech. This may be due to differences in auditory processing. “It might not be autism per se, but it could be something that’s related to communication in some way,” Perdue told Spectrum News.

Read more directly on Spectrum News or in the original paper. For information on enrolling in one of the Labs’s studies, visit their participant registry.

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