Since autism was first added to the psychiatric literature fifty years ago, there have been numerous studies and theories about its cause. Researchers still have not reached agreement regarding its specific causes. First, it must be recognized that autism is a set of a wide variety of symptoms and may have many causes. This concept is not unusual in medicine. For instance, the set of symptoms that we perceive of as a “cold” can be caused by literally hundreds of different viruses, bacteria, and even our own immune system. Autism is, undoubtedly, a biologically-based disorder. In the past, some researchers had suggested that autism was the result of poor attachment skills on the part of the mother. This belief has caused a great deal of unnecessary pain and guilt on the part of the parents of autistic children, when in fact, the inability of the individual with autism to interact appropriately is one of the key symptoms of this developmental disorder.

In support of a biological theory of autism, several known neurological disorders are associated with autistic features. Autism is one of the symptoms of these disorders. These conditions include tuberous sclerosis (an inherited disorder), the fragile X syndrome, cerebral dysgenesis (abnormal development of the brain), Rett syndrome, and some of the inborn errors of metabolism (biochemical defects). Autism, in short, seems to be the end result or “final common pathway” of numerous disorders that affect brain development. In general, however, when clinicians make the diagnosis of autism, they are excluding the known causes of autistic behaviors. However, as the knowledge of conditions that cause autism advances, fewer and fewer cases will be thought of as being “pure” autism and more individuals will be identified as having autism due to specific causes.

There is a strong association between autism and seizures. This association works in two ways: First, many patients (20% to 30%) with autism develop seizures. Second, patients with seizures, which are probably due to other causes, may develop autistic-like behaviors. One special and often misunderstood association between autism and seizures is the Landau-Kleffner Syndrome. This syndrome is also known as acquired epileptic aphasia. Some children with epilepsy develop a sudden loss of language skills–especially receptive language (the ability to understand). Many often also develop the symptoms of autism.

These children often, but not always, have a characteristic pattern of electrical brain activity seen on EEG (electroencephalogram) during deep sleep called electrographic status epilepticus during sleep (ESES). The usual age of onset of language loss or regression is around four years of age, which makes the Landau-Kleffner syndrome distinguishable from autism on these grounds, in that autism usually is first exhibited in younger children. However, in recent years, some children (very, very few) who did not exhibit overt (observable) seizures were found to have Landau-Kleffner syndrome.

The importance of these findings is that, although rare, the Landau-Kleffner syndrome can resolve spontaneously and in some cases can be treatable with prednisone, a steroid medication related to cortisone. This association between the Landau-Kleffner syndrome and autism has led many clinicians and families to search for the typical EEG pattern (ESES) in autistic individuals. This unusual EEG pattern is seen only in deep sleep, which usually requires prolonged recordings of up to 12 hours. Many, many autistic children and adults will display some abnormalities on their sleep EEG, but probably very few have true Landau-Kleffner syndrome that will respond to treatment.

It must also be noted that prednisone, in the very high doses used to treat Landau-Kleffner syndrome, almost invariably produces side effects, which may include weight gain, high blood pressure, diabetes, growth failure, stomach ulcers, irritability, destruction of the hip joint, and susceptibility to infectious disease (suppressed immune system). While most of these side effects are reversible, some of the complications of high dose prednisone therapy can be irreversible and even fatal.

Other treatments ranging from common anticonvulsant therapy to surgery have been proposed and are being tried for Landau-Kleffner syndrome. It is difficult to evaluate the true effects of any treatment for Landau-Kleffner syndrome due to the high rate of spontaneous resolution of symptoms (remission).

What is Rett Syndrome

Rett syndrome is a relatively rare condition that almost exclusively affects females. It occurs in one out of every 10,000 to 15,000 people.

Rett syndrome is part of a category of disorders known as pervasive developmental disorders (PDD), which are more commonly known as autism spectrum disorders. All of these disorders are characterized by varying degrees of:

• Impairment in communication skills and social interactions
• Restricted, repetitive, and stereotyped patterns of behavior.

Symptoms of Rett Syndrome

People who develop Rett syndrome initially go through a period of normal development that lasts between 6 and 18 months. After that, autism-like symptoms begin to appear. The little girl’s mental and social development regresses — she no longer responds to her parents and pulls away from any social contact. If she has been talking, she stops; she cannot control her feet; she wrings her hands. Some of the problems associated with Rett syndrome can be treated. Physical, occupational, and speech therapy can help with problems of coordination, movement, and speech.

Causes of Rett Syndrome

Scientists have discovered that a mutation in the sequence of a single gene can cause Rett syndrome. This discovery may help doctors slow or stop the progression of the syndrome. It may also lead to methods of screening for Rett syndrome. This would enable doctors to treat — and thus improve the quality of life of — these children much sooner.

For many children, symptoms improve with treatment and with age. Some children with autism grow up to lead normal or near-normal lives. Children, whose language skills regress early in life, usually before the age of 3, appear to be at risk of developing epilepsy or seizure-like brain activity.

During adolescence, some children with autism may become depressed or experience behavioral problems. Parents of these children should be ready to adjust treatment for their child as needed.

Statistics on Autism

Autism is one of the most common developmental disabilities. Individuals are of all races and ethnic and socioeconomic backgrounds. Current estimates suggest that approximately 400,000 individuals in the United States have autism.

Autism is three to four times more likely to affect boys than girls. It occurs in individuals of all levels of intelligence. Approximately 75 percent are of low intelligence, while 10 percent may demonstrate high intelligence in specific areas such as math.

Autism is a brain disorder that too often results in a lifetime of impaired thinking, feeling, and social functioning — our most uniquely human attributes. It typically affects a person’s ability to communicate, form relationships with others, and respond appropriately to the external world. The disorder becomes apparent in children generally by the age of 3.

Autism (sometimes called “classical autism”) is the most common condition in a group of developmental disorders known as the autism spectrum disorders.

Other autism spectrum disorders include:

• Asperger syndrome
• Rett syndrome
• Childhood disintegrative disorder
• Pervasive developmental disorder not otherwise specified (usually referred to as PDD-NOS).

Experts estimate that three to six children out of every 1,000 will have autism. Males are four times more likely to have it than females. Girls with autism tend to have more severe symptoms and greater cognitive impairment.