For me, the answer has to be, 'Yes,' I have seen many children who have mixed symptoms of both. There are many roads to the 'destination' of autism. There is increasing evidence that one such road is genetic, - the gene(s) in expressing itself / themselves create an anomaly in brain development,- (the evidence points to the adoption of an abnormal wiring pattern), which produces the symptoms of autism. Another road is now thought to be methylation difficulties, another through oxygen starvation, etc. All these differing 'roads' lead to brain dysfunction, which produces what we observe as autism. So, autism consists of a set of symptoms, (distorted sensory perception, faulure of socialisation, communication and imagination, stereotypical behaviours, etc). - These symptoms, all caused by brain dysfunction, are the way in which the condition we call 'autism' expresses itself, - so autism is an expression of brain dysfunction.
There are approximately one hundred billion neurons in the human brain, each cell having the potential to create ten thousand connections to other cells to form complex groupings of connections known as neural networks. This is an unbelievably complex operating system and when it becomes injured, the pattern of injury is therefore like a fingerprint, - unique to the child. Some children may have common symptoms, but no two children will display exactly the same problems. - This is why autism is a 'spectrum disorder,' with a child at one end of the autistic spectrum, displaying totally different problems to a child at the other end of the autistic spectrum.
We have already established that autism is caused by brain dysfunction, - well there are many other problems, which are also caused by brain dysfunction, one of which is cerebral palsy. CP can be caused by oxygen starvation, genetics (rarely), drug abuse, infection, jaundice, malnutrition, or one of many other causes. So it is brain dysfunction, which produces the sets of symptoms we know as CP just as it is brain dysfunction, which produces the sets of symptoms we know as autism.
So it is correct to say that both autism and CP are caused by brain dysfunction, - indeed, they are both 'expressions' of brain dysfunction, or if you like, 'brain injury.'
Now, the more severe and widespread the brain dysfunction, the more symptoms, (or expressions) will be displayed. So whilst a child who has suffered only a moderate amount of damage to the neural networks of the brain might display the symptoms or EITHER autism OR cerebral palsy, (or some other expression), the child who has suffered more severe damage, may display multiple expressions! These might include some symptoms which are considered to be on the autistic spectrum, alongside some symptoms which are considered to fall within CP (or indeed any other expression of brain dysfunction, - there are many!).So the answer is yes, I believe it is possible and not uncommon for a child to have a dual diagnosis of both autism and cerebral palsy. Does this mean they have two different conditions? No. They just suffer from severe brain dysfunction. At Snowdrop we provide programmes of rehabilitation for all types of and severity of brain injury