Is Autism Hereditary?

What is autism and is it hereditary? Autism is a developmental disorder that affects how a person interacts with others around them. The symptoms of autism are usually present from early childhood and are life long. Autism is a spectrum disorder, which means that it affects different people in different ways. Some people with autism are able to live full and productive lives, but others have profound learning disabilities and need special support.

What causes autism?

There are many different schools of thought as to what causes autism. For many years, it was suspected that the MMR vaccine given to children around twelve months of age was responsible for an increased risk of autism, which led to large numbers of parents boycotting the vaccine as a result. However, scientists have been unable to find any conclusive evidence to suggest that this assertion is true and the risks associated with catching measles, mumps or rubella are far greater than the risk of developing autism.

Is there a genetic component and is autism hereditary?

Parents who have one autistic child are often concerned about the possibility of having another child with autism, so the question of whether autism is hereditary is a very important one.

There is certainly some statistical evidence to suggest that having a close family member with autism increases the risk of autism in other family members. Early research studies carried out on identical twins suggested that autism traits were inheritable, a school of thought that has been backed up by further studies showing that if one identical twin had autistic traits, the other twin was extremely likely to exhibit the same traits.

More recent studies on the prevalence of autistic spectrum disorder have indicated that at least some families only have one member diagnosed with autism, which suggests that at least some occurrences of autism are “one-off” cases and not linked to hereditary factors. Statistics show that around 10% cases of autism are purely random occurrences in the general population, but there are many families with several autistic members and scientists believe that there are certain inheritable strains of autisms that are repeatedly passed down through the generations. Autism can also be a secondary diagnosis for other inheritable disorders, including Rett Syndrome.

What are the other causes of autism?

Studies on children with autism have shown unusual brain growth patterns between the ages of one and two, so there is obviously a link between brain structure and the symptoms of autism, although scientists are not sure if changes in brain structure cause autism, or vice versa. Environmental factors could also be partly to blame for some cases of autism—exposure to certain toxins is thought to have a bearing on whether a child will develop certain autistic attributes.

But whatever the cause, hereditary or not, the likelihood is that autism spectrum disorders are probably caused by a combination of environmental and genetic factors. Someone with a predisposition to autism may have their symptoms triggered by something unexplained early in life, but until more research is carried out on the causes of autistic spectrum disorder, there remain a great number of unanswered questions about autism.