Genomics plus human intelligence

The power of gene sequencing to solve puzzles when combined with human Read more

'Master key' microRNA has links to both ASD and schizophrenia

Recent studies of complex brain disorders such as schizophrenia and autism spectrum disorder (ASD) have identified a few "master keys," risk genes that sit at the center of a network of genes important for brain function. Researchers at Emory and the Chinese Academy of Sciences have created mice partially lacking one of those master keys, called MIR-137, and have used them to identify an angle on potential treatments for ASD. The results were published this Read more

Shape-shifting RNA regulates viral sensor

OAS senses double-stranded RNA: the form that viral genetic material often takes. Its regulator is also Read more

Steve Warren

Point mutation in fragile X gene reveals separable functions in brain

A new paper in PNAS from geneticist Steve Warren and colleagues illustrates the complexity of the protein disrupted in fragile X syndrome. It touches on how proposed drug therapies that address one aspect of fragile X syndrome may not be able to compensate for all of them. [For a human side of this story, read/listen to this recent NPR piece from Jon Hamilton.]

Fragile X syndrome is the most common single-gene disorder responsible for intellectual disability. Most patients with fragile X syndrome inherit it because a repetitive stretch of DNA, which is outside the protein-coding portion of the fragile X gene, is larger than usual. The expanded number of CGG repeats silences the entire gene.

However, simple point mutations affecting the fragile X protein are possible in humans as well. In the PNAS paper, Warren’s team describes what happens with a particularly revealing mutation, which allowed researchers to dissect fragile X protein’s multifaceted functions. Read more

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Supreme decision on DNA patents

In these days of political polarization, how often does the United States Supreme Court make a unanimous decision? When the case has to do with human genes and their patentability!

The case concerned patents held by Utah firm Myriad Genetics on the BRCA1 and 2 genes. Mutations in those genes confer an increased risk of breast and ovarian cancer. The patents in dispute claimed the genes themselves rather than just the technology for reading them.

Cecelia Bellcross, director of Emory’s genetics counseling program and an expert on breast cancer genetics counseling, reports that “in general, the clinical genetics community is jumping up and down, as are a lot of genetics lab directors and definitely patient advocacy groups.”

Myriad’s BRCA tests cost more than $3,000. Several competing firms announced that they would offer tests for the BRCA1 and 2 mutations at significantly lower prices.

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Fragile X clinical trials: this is not the end

A clinical trial testing a therapy for children with fragile X syndrome is closing down, after the sponsoring company announced that the drug, called arbaclofen, was not meeting its goals.

Readers of Emory Health magazine may remember Samuel McKinnon, an arbaclofen study participant who was featured in a 2012 article and video (below).

“We were surprised,” Samuel’s mother Wendy told us Monday. “But we knew going in that there were no guarantees.”

She reports that Samuel has made significant progress in the last couple of years. He likes playing and talking with the family’s new puppy, Biscuit. Samuel’s language skills have Ray Ban outlet blossomed and he will be headed to second grade this fall. But it’s hard to say whether that’s mainly because of the experimental drug or because Samuel has been continuing to grow and work hard in school and in therapy, she says.

A sizable fraction of patients in the study appeared to benefit from the drug, just not the majority of them, says Emory genetics chair Steve Warren.

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Fragile X clinical trial update

A recent issue of Emory Health magazine had an article describing the progress of clinical trials for fragile X syndrome, the most common inherited cause of intellectual disability. The article included interviews with the parents of a boy, Samuel McKinnon, who is participating in one of the phase III clinical trials here at Emory.

Last week, results for the phase II study for the same medication were published in Science Translational Medicine. The drug, called STX209 or arbaclofen, is one of the first designed to treat the molecular changes in the brain caused by fragile X syndrome. STX209 shows some promise in its ability to reduce social withdrawal, a key symptom of fragile X syndrome.

In one case, a boy was able to attend his birthday party for the first time in his life. In the past, he had been too shy and couldn’t tolerate hearing people sing Happy Birthday to You, the study’s lead author Elizabeth Berry-Kravis, MD, PhD from Rush University, told USA Today.

These results have generated excitement among autism researchers and specialists, because a fraction of individuals with fragile X mutations have autism and the same drug strategy may be able to address deficits in other forms of autism.

Some caveats:
1. Autism and fragile X are not the same thing.
2. This was a phase II study, the phase III results are yet to come.
3. The study authors are up front about saying that the “primary endpoint” (irritability) showed no difference between drug and placebo.

A team led by Emory genetics chair Steve Warren identified the gene responsible for fragile X in 1991, and Emory scientists have been important players in figuring out its effects on the brain.

Warren and colleague Mika Kinoshita are co-authors on a companion paper in STM on treatment of fragile X mice. A thoughtful review piece in the same issue of STM lays out current issues in developing therapies for “childhood disorders of the synapse.”

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