Researchers move 2 steps closer to understanding genetic underpinnings of autism

Today’s issue of the American Journal of Human Genetics (AJHG), describes what might be a corner piece of the autism puzzle—the identification and subsequent validation of a gene linked to the development of autism by three separate groups of scientists. An accompanying commentary by Dr. Dietrich Stephan, Director of the Neurogenomics Division at the Translational Genomics Research Institute’s (TGen), further explains the findings.

Autism is a perplexing disease whose cause remains unexplained. It has long been suggested that environmental factors, linked with genetics, play a role in causing the disorder. As recently as last week, researchers in California published a study that found no proof linking autism with a mercury-based preservative found in childhood vaccines. While there are no clear-cut answers, researchers are one step closer to understanding autism’s genetic cause.

In March 2006, Dr. Stephan, Director of TGen’s Neurogenomics Division, led a team of researchers at TGen and collaborators at the Clinic for Special Children (CSC) in Strasburg, PA, that identified a gene called CNTNAP2. When mutated, this gene indicated a predisposition to autism in a specific population of Old Order Amish children from Pennsylvania.

One of the most important principles in science is the ability to replicate results. Now, three groups of researchers from Yale University, the University of California, Los Angeles, and the Johns Hopkins University, have replicated the initial finding in the general population, unequivocally implicating this gene as causing the newly defined Type 1 autism. All three studies plus Dr. Stephan’s commentary are published in the January edition of AJHG.

According to Dr. Erik Puffenberger, Laboratory Director of the Clinic for Special Children, “Our previous finding of association between loss of CNTNAP2 function and autistic behavior has been validated in the general population. This is a very exciting step for autism research. It also highlights the enormous potential of the ‘small science’ approach. Our initial work used only four affected Amish children. Careful study of these four patients uncovered the association between CNTNAP2 and autistic behaviors. From that small beginning, CNTNAP2 has now been implicated as a significant risk factor for autism.”

Autism spectrum disorder (ASD) is a broadly used term for a set of developmental disorders that emerges in infants and young children. ASD impairs a child's intuitive thought, language and social development to varying degrees. Most individuals diagnosed with ASD require lifelong supervision and care; the most severely affected are unable to speak. ASD is the fastest growing developmental disability in the U.S. Two decades ago, roughly one child in 10,000 was diagnosed with ASD; it now affects one in 150 births.

“The field of genetics is replete with examples where researchers are unable to reproduce results. Here we have independent confirmation in multiple groups using large samples sizes,” said Dr. Stephan. “Now that the results of the initial CNTNAP2 gene finding have been replicated, it strongly supports the notion that the ‘broken version’ of CNTNAP2 is recognized as a cause of autism in the general population.”

In collaboration with the Phoenix-based Southwest Autism Research & Resource Center (SARRC), a nonprofit community-based organization dedicated to research, education and resources for individuals with ASDs and their families, TGen will apply these research findings to children in Arizona who have been diagnosed with ASD.

“The heterogeneity of the disorder has frustrated our past efforts in the search for causes of autism,” said Dr. Raun Melmed, medical director and co-founder of SARRC. “This exciting discovery will further our capacity to individualize approaches to the diagnosis and treatment of autism.”

The next step, noted Dr. Stephan in the commentary, is to develop a diagnostic to test for the CNTNAP2 mutation. If physicians could implement behavioral interventions early enough, children with autism may have a better chance of developing normally.

Source: The Translational Genomics Research Institute

Related stories:

Autism risk higher in people with gene variant
Scientists have found a variation in a gene that may raise the risk of developing autism, especially when the variant is inherited from mothers rather than fathers. The research was funded by the National Institute of Mental Health (NIMH), part of the National Institutes of Health.
Families will make case for vaccine link to autism
(AP) -- Families claiming that a mercury-based preservative in vaccines triggers autism will challenge mainstream medicine Monday as they take their case to a federal court. They seek vindication and financial redress from a government fund that helps people injured by shots.
Researchers find gene location that gives rise to neuroblastoma, an aggressive childhood cancer
Using advanced gene-hunting technology, an international team of researchers has for the first time identified a chromosome region that is the source of genetic events that give rise to neuroblastoma, an often fatal childhood cancer.
Study uses music to explore the autistic brain's emotion processing
Music has a universal ability to tap into our deepest emotions. Unfortunately, for children with autism spectrum disorders (ASD), understanding emotions is a very difficult task. Can music help them? Thanks to funding from the GRAMMY Foundation Grant Program, researchers at UCLA are about to find out.
Mental disorders in parents linked to autism in children
Parents of children with autism were roughly twice as likely to have been hospitalized for a mental disorder, such as schizophrenia, than parents of other children, according to an analysis of Swedish birth and hospital records by a University of North Carolina at Chapel Hill researcher and colleagues in the U.S. and Europe.
Anti-psychotic drug use soars in UK children, too
(AP) -- American children take anti-psychotic medicines at about six times the rate of children in the United Kingdom, according to a comparison based on a new U.K. study. Does it mean U.S. kids are being over-treated? Or that U.K. children are being under-treated?
Transitioning patients with pediatric disease to adulthood
Growing pains can mean one thing for a typical adolescent and quite another to an older teen with cerebral palsy attempting independence in an adult world. A unique program, the Indiana University School of Medicine Center for Youth and Adults with Conditions of Childhood (CYACC) is helping these youths spread their wings and live more independently.
Surprising language abilities in children with autism
What began as an informal presentation by a clinical linguist to a group of philosophers, has led to some surprising discoveries about the communicative language abilities of people with autism.

News discussion:

Medicine & Health news