The vast majority of people can probably tell you that autism is associated with problems relating to others and interacting socially. Far fewer people will be able to tell you about another developmental disorder that is also associated with social interaction difficulties: Williams syndrome. But people with Williams syndrome are more likely to be overly friendly and lack so-called “stranger danger”.
One in 18,000 individuals are estimated to have Williams syndrome and there are around 3,500 people with the disorder in the UK. It’s a genetic disorder caused by the deletion of about 28 genes from chromosome 7. It is known to occur equally in males and females and is a lifelong developmental disorder.
Heart defects, distinctive facial features, difficulties feeding and a failure to thrive in early infancy can be indicative of the disorder and require further exploration (with subsequent genetic confirmation). As Lizzie Hurst, chief executive of the Williams Syndrome Foundation UK emphasises, “early diagnosis can change the landscape” as outcomes for children with educational and therapeutic early intervention are greatly improved.
Outgoing and over-friendly
Since it was first described by cardiologist J.C.P. Williams in 1961, Williams syndrome has been of particular interest to psychologists. While up to a half of those with the disorder have cardiovascular problems, the focus for psychologists is on cognitive and behavioural issues.
Many individuals function with mild to moderate intellectual difficulties. However, this description does not emphasise the profile of sensitivities and heightened awareness that occurs alongside extensive difficulties. Many individuals are highly verbose (far beyond their level of comprehension), some have musical expertise and the vast majority are highly social. “Outgoing”, “over-friendly”, and “emotionally sensitive” are descriptions frequently used to describe the ‘Williams syndrome personality’.
Specific difficulties are often experienced with spatial skills – for example drawing, completing puzzles or reading maps. Some individuals can develop very specific interests that can dominate their thoughts and up to 95% have a specific over-sensitivity to sound, called hyperacusis. This sensory sensitivity can sometimes be linked to heightened anxiety. Recent research from our Williams syndrome research group at Durham University suggests that this anxiety can be related to difficulties with daily functioning.
Is it the opposite of autism?
Our research often includes people with Williams syndrome and Autism in the same studies. There are clear differences between the disorders but it’s not quite accurate to say they are “polar opposites”, which has sometimes been suggested.
While there are some very important differences between Williams syndrome and Autism there are also informative overlaps. Let’s deal with the differences first. A striking feature of Williams syndrome is high sociability and empathy for others, which is very different to that associated with typical development. Individuals with the disorder are often socially fearless and can be impulsive in social interactions, even with strangers. A paper we recently published showed the lack of stranger danger awareness that can lead to heightened vulnerability.
While Autism is also associated with atypical social functioning, social isolation is more common. In this basic sense the disorders seem like polar opposites. But this description doesn’t capture the vast variability seen in both groups. In early development the overlap between disorders in terms of social communication difficulties can be particularly apparent.
In rare cases individuals can be diagnosed with both Williams syndrome and Autism and they can experience more difficulties with aspects of social functioning and communication (especially language).
So the social profiles of the disorders seem very different, but where do they overlap? There are several cognitive domains that are problematic in both disorders. Deficits of non-verbal behaviour such as eye contact, facial expressions, interpreting gestures, are widely reported. Additionally, we know that both disorders are associated with sensory processing difficulties, heightened anxieties and repetitive behaviours or restrictive interests.
The similarities and differences between Williams syndrome and Autism can be hugely beneficial to our understanding of both disorders. The clear cut genetic nature of Williams syndrome, as well as overlaps of behavioural and clinical characteristics, can be extremely useful to our understanding of the more complex etiology of Autism. Additionally, we can also use these two disorders to inform our theoretical framework for typical development.
Though rare, understanding more about Williams syndrome is paramount. Knowledge of syndrome-specific characteristics as well as cross-syndrome features of cognition and behaviour throughout development will allow us to improve current interventions and develop support strategies for individuals with the disorder and their families.