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Scientists trying to unravel the mystery of Autism

10-13-2006–
HACKENSACK, N.J. — A single word — autism — changed Christine Bakter’s life.

It explained her son Alex’s strange behavior. It clouded her dreams for her second son, Ben, who was just 3 weeks old when Alex was diagnosed. Would he, too, have autism?

And it plunged her family into a world of scientific research — a world to which they have contributed as much as they’ve received.

Autism researchers are pushing to identify the genetic changes linked to autism. They’re unraveling the brain’s role in reading facial expressions, understanding spoken language and making friends. They’re trying to develop effective ways to teach those affected.

They’re helped by people like the Bakters who — in the midst of their own difficult lives — are offering themselves for research.

Baby Ben was enrolled in a study of 300 siblings of children with autism — children who are 50 times as likely as the general population to develop the disorder. Alex is signing up for a study on computer software that trains autistic children to make eye contact and read facial expressions. The whole family has given blood samples for the Autism Genome Project, the largest-ever genetic study of autism.

But despite dramatic increases in research and funding, surprisingly little is known about autism. It still has no known cause or cure.

“Autism is an extremely complex disorder,” says James Millonig of Rutgers University and the University of Medicine and Dentistry of New Jersey. He is a mouse geneticist and one of the state’s top autism researchers. “The more ways we attack it scientifically, the better off we are.”

Among the questions researchers are trying to answer:

“¢ Why is the number of cases climbing, and how fast is it rising? Changes in the way autism is defined have caused many more children, once labeled mentally retarded or otherwise disabled, to be diagnosed with autism. Even allowing for that increase, it’s clear that the rate of autism is rising. But how fast? Do certain groups of people, or locales, have more autism?

“¢ Which genes, what environmental factors and what combinations of the two cause autism? Is a child born with a “susceptibility” to autism that is triggered by a virus or a certain chemical? Can steps be taken to identify at-risk children and protect them?

“¢ What happens in the brain that results in an autistic person’s inability to “read” a face or take in social cues? Why the hand-flapping, finger tics and rocking? What action of the brain cells allows us to listen and respond with meaning, inflection and expression?

“¢ Could screening tests identify a child before symptoms develop? Can differences in blood, brain images or even head circumference be used for diagnosis, so that treatment can begin as early as possible?

“¢ And what alternative treatments are effective? Do diets free of wheat products help? How about treatments to strip metals from the body or high-pressure oxygen chambers, vitamin injections or acupuncture?

GENETIC RESEARCH

The research is taking place in labs across the nation.

At the Center for Advanced Biotechnology and Medicine, a joint institute of Rutgers and University of Medicine and Dentistry of New Jersey in Piscataway, researchers are examining thousands of mice with a genetic defect similar to one found in humans with autism. They are hoping to understand the effects of this mutation on their behavior and brain chemistry.

In the New Jersey Language and Autism Genetics Study at Rutgers, cell DNA is scanned for gene changes shared by people with autism and their relatives with language impairments. This may pinpoint the genes involved with language use — and one day lead to a genetic test for autism.

“Trying to understand autism is like trying to do one of those really hard jigsaw puzzles,” says Linda Brzustowicz, a professor of genetics at Rutgers and a psychiatrist at Robert Wood Johnson Medical School. “Anytime you get a few more pieces in place, it makes others easier to fit in.”

Most research focuses on the causes of autism.

Clearly, genes play an important role. Virtually every special school for children with autism has at least one pair of siblings. Studies of identical twins have shown that if one twin is diagnosed with autism, nine out of 10 times the other will be, too.

“This is a highly genetic disorder,” says Emanuel DiCicco-Bloom, professor of neuroscience and cell biology at Robert Wood Johnson, part of UMDNJ.

But it’s not a simple matter of one gene being passed on by both parents. Rather, several genes must mutate simultaneously for autism to develop — “at least three genes, if not up to 15,” he says.

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Several research groups, in New Jersey and elsewhere, are trying to discover which genes are involved. They use samples from gene banks like the one storing the Bakters’ DNA, and from the Rutgers University Cell and DNA Repository of 518 families, each with multiple autistic children.

The researchers are looking for genes that govern the development of regions of the brain that appear different in autopsies of people with autism. They look for gene changes linked to such symptoms of autism as repetitive movement and poor communication skills.

In an important development, New Jersey researchers have found one gene involved in 40 percent of autism cases. It is associated with reduced growth in the cerebellum, one of many parts of the brain that affect movement and the ability to switch tasks.

The next step is to understand how these DNA changes cause the brain to develop differently. “We’ll create mice, to address this question,” Millonig says. The changes in their brain anatomy will add to the understanding of how the human brain develops.

Genetics, of course, doesn’t explain everything. Even with identical twins, there is still a 10 percent chance that if one develops autism, the other will not.

Environmental scientists look at that 10 percent and ask why. What difference was there in the way the baby developed — in utero, and in the first months of life — that explains why the child doesn’t have the disorder? Was it the position in the uterus? Exposure to a chemical or a virus? A medication the baby or the mother took?

A lot of attention has focused on vaccines, which — until the last lots expired in early 2003 — contained thimerosal, a mercury preservative. The symptoms of autism often appear about the same time that toddlers receive a batch of immunizations, which has led some parents and scientists to suspect a connection.

A study by the national Institute of Medicine concluded in 2004 that neither thimerosal-containing vaccines nor the measles-mumps-rubella vaccine is associated with autism. Several studies, it said, “consistently provided evidence of no association.” However, the issue hasn’t been put to rest for some people.

In the search for other environmental causes, researchers have tested dust, water and air in the homes of dozens of children with autism.

Scientists at the Center for Childhood Neurotoxicology and Exposure Assessment, a joint program of UMDNJ and Rutgers in Piscataway, are looking at whether levels of metals, pesticides, volatile organic compounds and other pollutants in these children’s homes are higher than normal.

Preliminary results indicate they are not, said Clifford Weisel, a professor of environmental and occupational medicine at Robert Wood Johnson.

In particular, researchers are interested in the type of autism in which babies develop normally until about the age of 2, then regress. Could there be something about the way these children are affected by their environment — by mouthing their toys or by ingesting more pollutants — that explains the regression?

Other researchers are exploring how the brain works and what goes wrong in children with autism. A typical baby, for example, quickly learns to focus on a caregiver’s face and imitate the expression she sees. But a child with autism looks elsewhere: at the caregiver’s plaid shirt, for example, or the light switch over her shoulder. Without that dance of smile and response, the autistic child misses out on social understanding.

With the big money going to basic research into the causes of autism, some on the front lines — those who work with children and adults who have autism — are frustrated.

Autism Speaks, the largest private philanthropy for autism research, and the Governor’s Council on Autism have invited applications for funding of treatment studies this fall. But the big pharmaceutical companies stay out, because there’s no pill to cure autism — and little prospect of finding one, because medicine can’t make the brain develop differently.

The absence of drug-company interest is a shame, says Charles Cartwright, a psychiatrist and head of UMDNJ’s Center for Autism. He prescribes dozens of drugs — strong ones, for long periods — to patients with severe autism, to suppress seizures or self-injurious behavior. Little research has been done on their long-term use in such patients.

By Lindy Washburn
The Record (Hackensack N.J
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