Unfortunately, we cannot diagnose autism until it has already developed in the person - the earliest diagnosis takes place in the second year of life when signs of communication problems appear in the child (we don't really know whether it develops or not after birth, whether it is already there before birth).

Professor Carlos Pardo-Villamizar , team leader, said to the BBC "These findings open new possibilities for understanding the dynamic changes that occur in the brain of autistic patients during childhood and adulthood. Although they may lend themselves to the development of new medical treatments for autism, much more research would be needed to establish the validity of this approach."

The prevalence of autism has grown over the last twenty years. Some people wonder whether there may be some environmental trigger. Others suggest that diagnosis is much more accurate these days. Many people in the past with Asperger's Syndrome were not classed as autistic - today they are, hence the numbers of autistic people today are higher than before. In most of the world, Asperger's Syndrome was not recognised until 1994.

TYPES OF AUTISM

Several types have been defined along the autism spectrum, differing in the severity of the symptoms and total disability and in the combinations of autistic impairments with other disabilities. We present brief accounts of some of these.

CLASSIC AUTISM, AUTISTIC DISORDER OR KANNER'S SYNDROME

The psychiatrist Leo Kanner of John Hopkins University first described and named this syndrome based on 11 of his child patients between 1932 and 1943. He noted the following common features:

-- a profound lack of affect or emotional contact with others

-- an intense wish for sameness in routines

-- muteness or abnormality of speech

-- fascination with manipulating objects

-- high levels of visuo-spatial skills, but major learning difficulties in other areas

-- attractive, alert and intelligent appearance.

Kanner's observations became the criteria for early studies of the prevalence of autism. Children (and adults) with these features have the full triad of impairments and represent the most severely disabled end of the autism spectrum of disorders.

Autism organizations were first formed in the 1960s and 1970s by the parents of children with classic autism. More recently these organizations have been enlarged in scope and functions to serve those with a wider range of autistic and pervasive developmental disorders.

ASPERGER'S DISORDER

First described by Hans Asperger of Vienna in 1944, whose work was not generally known in English translation until 1981, the disorder was not listed in the Diagnostic and Statistical Manual of Mental Disorders (DSM) http://www.autism-biomed.org/dsm-iv.htm until 1994.

Asperger's shares with autism a severe and sustained impairment in social interaction, and restricted and repetitive patterns of behaviour and interests. But people with Asperger's do not have the significant delays in language, cognition, self-help skills or adaptive behaviour that are typical in autism; they are often physically clumsy and awkward, more obviously than children with classic autism. Asperger's is often not recognized easily or early, and may be misdiagnosed as Tourette's Syndrome, Attention Deficit Disorder, Attention Deficit Hyperactivity Disorder, Oppositional Defiance Disorder, or Obsessive-Compulsive Disorder. As with autism, the disorder is lifelong and no complete cure is known. Asperger's disorder may be the largest type on the autism spectrum, affecting 35 in every 10,000 people.

People with Asperger's may have an exceptional talent or skill with which they are preoccupied. It is conjectured that several people of remarkable genius may have had Asperger's--including Albert Einstein, Vladimir Nabokov, Ludwig Wittgenstein, Bela Bartok and Andy Warhol. Of Canadian interest is a front-page story in The Globe and Mail (1 February 2000) entitled "Was Glenn Gould autistic?" The possibility that Asperger's Syndrome could explain Gould's social deficiencies, obsessive perfectionism and intolerance of change was raised in the 1996 biography by psychiatrist Peter Oswald, Glenn Gould: The Ecstasy and Tragedy of Genius, and is now elaborated by the musicologist Timothy Maloney. Gould was acutely sensitive to light, sound and temperature, and had a phobia about shaking hands as well as a limited range of preferred foods. His bizarre mannerisms as a concert performer could be understood as uncontrollable expressions of Asperger's.

RETT'S SYNDROME

First identified by the Australian, Dr Andreas Rett, in 1965, Rett's is a complex neurological degenerative disorder that affects only girls. It is rarer than some of the types on the autism spectrum, affecting 1 in every 10,000 girls. From onset at about 18 months of age, its victims become profoundly and multiply disabled and dependent on others for all their needs. Key symptoms include hypotonia (reduced muscle tone) and such autistic-like behaviours as wringing and waving hands. The discovery of the gene for Rett's syndrome was reported in October 1999.