2 April 2010
By Dr Shiv Gautam
Understanding autism for a better society
Boys are four times more likely to be diagnosed with autism than girls, india has 2 million cases
The disorder is not rare. Most autistic people in India have not been diagnosed and do not receive the services they require. This problem occurs in several countries.
People with autism may also have unusual patterns of language development, narrow interests and engage in repetitive and sometimes challenging behaviours. Asperger’s Syndrome is a form of autism in which speech development and IQ are normal, but in which social disability can be compounded by depression and mental health problems. Some people with autism demonstrate significantly challenging behaviours; most need specialist support and care.
First identified more than 50 years ago, autism affects half a million people in the UK — tens of millions worldwide — and is one of the most common developmental disorders. Boys are four times more likely to be diagnosed with autism than girls. Autism affects people of all racial, ethnic and socio-economic backgrounds.
Recent estimates have placed the prevalence of autism in the US at approximately 1 in 150 people. At India’s current population, this means there are more than two million autistic persons in the country. Of course, this estimate assumes that there are no significant variations in this rate worldwide, which is a question that has not yet been addressed by epidemiologists outside the West.
While the disorder is not rare, the majority of autistic people in India has not been diagnosed and do not receive the services they need. This problem occurs in many countries, but is especially true in India where there is a tremendous lack of awareness and misunderstanding about autism among the medical professionals, who may either misdiagnose or under diagnose the condition.
Whereas autism once accounted for 3% of all developmental disabilities, in California it now accounts for 45% of all new developmental disabilities. Other countries report similar increases.
What causes Autism?
Finding the causes of autism is one of the most challenging areas of medical science. No one knows exactly why, but the brain develops differently in people with autism. The absence of a clear understanding about what causes autism makes finding effective therapies very difficult. It is now widely accepted by scientists that a predisposition to autism is inherited with the underlying genetic cause of up to 40% of autism cases identified. It is not clear why a genetic predisposition affects some family members and not others. Improved detection, identification and diagnosis means that we now estimate that 1 in 100 people have an autism spectrum disorder. There are currently no biological tests to confirm the disease. Identification of the condition is at present based solely on observed behaviour. Research is on to establish the part played, if any, by environmental factors either prenatally or after a child is born. Autism is no longer attributed, as it once was, to lack of affection of the mother.
Genetics of Autism
Genetics appear to play an important role in causing some cases of autism. Several studies have shown that when one identical twin has autism, the other often has autism. In contrast, when one fraternal twin has autism, the other is rarely autistic. Studies trying to identify specific genes associated with autism have been inconclusive. Currently, it appears that 20 or more genes may be associated with autism. This is in contrast to other disorders, such as Fragile X or Rett’s syndrome, in which single genes have been identified.
A large number of studies have found that autistic individuals often have compromised immune systems. In fact, autism is sometimes described as an autoimmune system disorder. One working hypothesis of autism is that the child’s immune system is compromised genetically and/or environmentally (for example exposure to chemicals). This may predispose the child to autism. Then, exposure to an (additional) environmental insult may lead to autism (for example the MMR vaccine) or mercury-containing vaccine preservatives (for example thimerosal).
If parents have a child with autism, there is an increased likelihood that their children will also develop autism. Many studies have identified cognitive disabilities, which sometimes go undetected, in siblings of autistic children. Siblings should be evaluated for possible developmental delays and learning disabilities, such as dyslexia.