Causes of Asperger Syndrome

Books about childhood Aspergers

Scientists have invested a great deal of time and effort into finding causes of Asperger's syndrome in recent years. While it is widely accepted that there are hereditary factors in play, no definitive answer has yet to be found. However, researchers have uncovered many new information about the disorder, and promising new theories have been based on those discoveries, which may bring scientists closer to identifying the causes of this disorder.

Asperger Syndrome, an Autism Spectrum Disorder

Asperger syndrome is one of the mildest of the pervasive developmental disorders on the autism spectrum. While many with Asperger syndrome display the core symptoms of autism, with impairments in communication and social interaction, repetitive behaviors, limited interests, and rigid routines, symptoms are generally less severe.

While other spectrum disorders may carry the risk of mental retardation, Asperger syndrome does not. In fact, IQ scores well above average are not uncommon in people with Asperger syndrome. Speech and language delays, common in autism, are not an issue with Asperger syndrome, with most children affected meeting developmental benchmarks. Language problems relate to social communication in cases of Aspergers.

As is true of many autism spectrum disorders, Asperger syndrome is most prevalent in males. According to, the ratio is estimated at approximately four males diagnosed for every one female.

Asperger Syndrome Cause: Prominent Theories


The pediatrician who first documented this disorder in Vienna, Hans Asperger, noted that parents, especially fathers, of his patients often displayed symptoms similar to those prominent in their children. Since those early days, a mountain of research has been done on the genetic components of the disorder. Although this research has yet to identify a specific gene, there is a general consensus among experts that genetic connections do exist, given the tendency of Asperger syndrome to run in families, as well as the frequent appearance of its characteristic symptoms in family member of affected individuals.

Many believe that a number of genes are probably involved in making children vulnerable to the disorder, and these can be affected in varying combinations, accounting for the wide variations in symptoms and severity seen in people with Asperger syndrome. In one of the largest autism and genetic studies ever conducted, known as the Autism Genome Project, rare genetic variations were noted more frequently in children diagnosed with autism as opposed to children who did not have the disorder. In addition, ABC News Health reported the findings of a large study showing a connection between autism and possible genetic causes.

Environmental Insult

Another area that has been studied extensively in recent years is the possibility of environmental factors triggering the development of Asperger syndrome. This school of thought has arisen largely as a means of explaining the dramatic rise in recent years in cases of autism spectrum disorders, including Asperger syndrome. Some theories suggest that environmental factors may work hand in with genetic vulnerabilities to bring about the disorder. Among the possibilities that have been focused on are heavy metal toxicity, certain childhood vaccines, viral infections that occur during gestation or shortly after birth, and exposure to teratogens, which are agents that cause birth defects.

Some maintain that a combination of environmental triggers and a genetic predisposition to developing pervasive developmental disorder is the root cause. The challenge is determining which triggers and which genetic problems are present.


Early autism experts largely subscribed to the theory that Asperger syndrome and other forms of autism were psychiatric disorders that could be traced to poor parenting. This theory, popularly known as "refrigerator mothers," has been thoroughly discredited as scientists have found evidence relating autism spectrum disorders to genetics rather than psychological issues. Unfortunately, there are still a few who believe in this theory, with some professionals still publishing papers and books claiming it as a cause for Asperger syndrome, despite abundant scientific evidence to the contrary.

While many theories have passed by the wayside over the years, many of today's theories are more firmly grounded in science. Researchers have made significant inroads into understanding the processes at work in the development of Asperger syndrome and other autism spectrum disorders. This new level of understanding, along with advancements in technology, has given scientists a stronger foundation of knowledge upon which to base further investigations into the causes of these disorders.

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Causes of Asperger Syndrome