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Category: Autism (page 1 of 2)

09.20.2012

arbaclofen and autism

Arbaclofen

Arbaclofen shows promise as a treatment for Fragile X syndrome and autism.

An experimental drug called arbaclofen has helped improve outcomes in patients with Fragile X syndrome. Fragile X syndrome causes cognitive and social dysfunctions that are similar to autism. Researchers are hoping this treatment may have broader applicability,  though that remains to be seen. From NPR:

An experimental drug that helps people who have Fragile X syndrome is raising hopes of a treatment for autism.

The drug, called arbaclofen, made people with Fragile X less likely to avoid social interactions, according to a study in Science Translational Medicine. Researchers suspect it might do the same for people with autism.

Arbaclofen appears to work by tamping down overactive brain signals that can make it hard to navigate social interactions.

There’s a good chance it will help people with autism unrelated to Fragile X because they have similar problems with social interactions, says Mark Bear, a researcher at MIT and a co-founder of Seaside Therapeutics, which makes arbaclofen.

“It would be, I think, unrealistic to expect that this drug would be uniformly beneficial to all people that have an autism diagnosis,” Bear says. “But I think we can still be quite optimistic that it can be beneficial to a subset of those patients.”

09.06.2012

branched-chain amino acid deficiency linked to rare form of autism

Lots of interesting reads in Scientific American & Nature these past few weeks.  Ewen Callaway of Nature magazine brings us this story:

A rare, hereditary form of autism has been found — and it may be treatable with protein supplements.

Genome sequencing of six children with autism has revealed mutations in a gene that stops several essential amino acids being depleted. Mice lacking this gene developed neurological problems related to autism that were reversed by dietary changes, a paper published today in Scienceshows1.

“This might represent the first treatable form of autism,” says Joseph Gleeson, a child neurologist at the University of California, San Diego, who led the study. “That is both heartening to families with autism, and also I think revealing of the underlying mechanisms of autism.”

The children came from three families with Middle Eastern ancestry; in each case the parents were first cousins. Studying such families makes the hunt for the rare recessive mutations underlying some forms of autism simpler than it would be among the general population, Gleeson says, because the odds are higher that children will be born with two copies of the recessive mutation.

In each family, Gleeson’s team identified mutations that inactivate the enzyme BCKD-kinase, which normally prevents the body from breaking down branched-chain amino acids called leucine, isoleucine and valine after a meal. Humans cannot synthesize these amino acids and must obtain them from food.

“We predicted that patients would burn through these amino acids,” says Gleeson. The prediction was correct: after eating, the children had low blood levels of the branched-chain amino acids. Mice lacking the gene that codes for BCKD-kinase also had low levels of the amino acids in their blood and tissue.

The sample size of six is extremely limited due to the rarity of the disease, so we don’t know if the result are generalizable. But the results are interesting nonetheless.

04.06.2012

a big leap in autism research

Three teams of scientists have made progress identifying gene mutations that  may lead to autism. They have also found further evidence autism risk increases among older parents, especially when the father is over age 35.  Three unaffiliated groups have completed studies that are published on the website of the journal Nature  this week. From a summary of the research findings in the New York Times:

The three research teams took a similar approach, analyzing genetic material taken from blood samples of families in which parents who have no signs of autism give birth to a child who develops the disorder. This approach gives scientists the opportunity to spot the initial mutations that accompany the condition, rather than trying to work though possible genetic contributions from maternal and paternal lines. In all three studies, the researchers focused on rare genetic glitches called de novo mutations.

De novo mutations are not inherited but occur spontaneously near or during conception. Most people have at least one, and the majority of them are harmless.

In one of the new studies, Dr. Matthew W. State, a professor of genetics and child psychiatry at Yale, led a team that looked for de novo mutations in 200 people who had been given an autism diagnosis, as well as in parents and siblings who showed no signs of the disorder. The team found that two unrelated children with autism in the study had de novo mutations in the same gene — and nothing similar in those without a diagnosis.

“That is like throwing a dart at a dart board with 21,000 spots and hitting the same one twice,” Dr. State said. “The chances that this gene is related to autism risk is something like 99.9999 percent.”

More here. [New York Times]

“De novo mutations revealed by whole-exome sequencing are strongly associated with autism” [Nature, abstract available]


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