The largest ever study in this field has found that babies are ten times more at risk of developing autism if they have a sibling who has the disorder.
The study found that a child’s risk is doubled if they have a cousin who has the disorder.
The study was initiated at King’s College London after several parents questioned scientists about the chances of them having a second child with the developmental disorder.
The study involved analysis of the medical records of all children born during 1982 to 2006 in Sweden, to determine the relationship between those diagnosed with autism. Of the two million children involved, 14516 received a diagnosis of ‘autism spectrum disorder.’ Children in this category experience difficulty in socialising with other children and have difficulty in recognising subtle signs in people’s body language, speech and facial expressions.
There is however a wide gap in the severity of the disorder and how those affected respond to it.
Some of the sufferers go into their own worlds and rarely smile. Others become aggressive and are obsessive about following particular routines.
Many who suffer from this disorder need support into adulthood, with many parents finding it extremely difficult to cope.
The author of the study from King’s College London, Dr Sven Sandin, in collaboration with Karolinska Institute in Stockholm, has issued a warning that parents who already have an autistic child should give careful thought to increasing their family size.
He stated that some parents will want to avoid having another child with the disorder, whilst others will not view it as a problem at all.
Dr Laura Cockburn, from the National Autistic Society, stated that parents of autistic children are fully aware of the challenges they face in raising them. She stated that parents can only base their decision on whether to have another child on what best suits their family. She further added that many of the babies who are diagnosed with the disorder come from families where no history of the condition is present.
It has been found that autism is more common in boys than in girls. The chance of having a male child on the autistic spectrum is said to be around one in 50. This level is increased to one in five if the little boy is born into a family with an autistic child.
In sharp contrast, the chance of having a girl with autism is around one in 200. The chance of a baby girl developing the condition if she has a sibling with the disorder is one in 20.
The study found that 50% of the child’s chance of developing the disorder is genetic and environmental factors account for the other 50%. In previous studies done on twins, it was found that genetic factors play a much higher role at 90%.
Dr Sandin has stated that most of the environmental factors, such as premature births, are out of the parents’ control.
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