Do Children with Craniosynostosis Have More Difficulties with Autism? A Review of the Evidence

Do Children with Craniosynostosis Have More Difficulties with Autism? A Review of the Evidence

Hearing that your child has a diagnosis of craniosynostosis can raise many worries and questions, such as ‘how is this going to affect them when they’re older?’.

Craniosynostosis is a condition in which the joints between the bones of a baby’s skull close too early. This can affect how the skull grows, and may cause the head to develop an unusual shape. The most common types of craniosynostosis are sagittal, affecting the midline joint at the top of the skull, and metopic, affecting the suture that runs from the nose to the top of the head. Most children are treated with surgery, while others may not need surgery if it is a mild form of the condition.

Some studies have suggested that children with craniosynostosis may be more likely to experience developmental difficulties, including autism spectrum disorder (ASD). Understandably, this can be concerning for families. While ASD is estimated to affect 1% of the general population, there is limited understanding on whether children with craniosynostosis are more likely to have ASD than peers without the condition.

To explore this question, Doctors Ljubicic, Osborn and Roberts from the University of Adelaide reviewed all available studies that explored autism and social development in children with single suture craniosynostosis. They included studies that reported either formal ASD diagnoses or results from questionnaires designed to measure ASD traits and social functioning. They also included studies with numerical data that could be combined to give an overall estimate.

The researchers excluded studies that explored outcomes of multiple suture craniosynostosis and other craniofacial conditions, and also studies that included children who were selected for the studies based on pre-existing social difficulties. They combined information from 12 studies involving more than 2,000 children to gain a clearer understanding of the evidence.

In studies looking at diagnoses of ASD, on average, 4% of children with craniosynostosis were diagnosed with autism, ranging from 1% to 9%. ASD diagnoses appeared somewhat more common in children with sagittal, and metopic synostosis, although these findings were based on a small number of studies. However, one large study did not report findings separated by suture type, making it difficult to know whether its results would have changed these estimates. Three studies of primary school-aged children reported that around 7% had an ASD diagnosis, whereas one large study found a rate of 1% in older children and adolescents.

Research based on parent-rated ASD questionnaires found that about 14-15% of children with craniosynostosis had scores indicating a high degree of ASD-related traits. In one study, children with sagittal synostosis had slightly higher levels of these traits than children of the same age and sex without craniosynostosis. Around twice as many children in the craniosynostosis group had scores in the clinically important range, although this difference was small and not statistically significant.

Studies measuring social functioning reported that 12% of children with craniosynostosis showed delays in social functioning. Rates were higher in children with metopic, than sagittal synostosis. Fewest social delays were seen in the pre-surgery group, followed by children who did not require surgery for their synostosis. Children who had undergone surgery showed the highest rates of social difficulties. It is important to note that the ages of children in those groups could have impacted the outcomes, with fewest problems in infancy, increasing slightly in preschool, and more prevalent in primary school children.

To summarise, children with single-suture craniosynostosis generally appeared to have similar functioning to their peers without the condition, with most effect sizes small and not statistically significant. It is important to note that children who experience social difficulties or who have reports of ASD traits may not meet the diagnostic criteria for ASD. While social challenges can overlap with characteristics of ASD, it is important to note that difficulties with social functioning can also occur in other developmental conditions.

This study has some important limitations. The studies varied in how they measured the rates of autism and social functioning difficulties, and reported outcomes at different ages. This raises questions about how useful it is to look at the combined data. Also, the majority of studies did not compare outcomes to a control group. Literature suggests that craniosynostosis is known to be more common in males, and so is ASD. It’s possible that higher rates of ASD observed in children with craniosynostosis may partly reflect that more boys have craniosynostosis. Therefore, it is important for future studies to have sex-matched control groups.

It remains unclear what impact different suture types may have on the development of ASD and social functioning deficits, as the largest study in this review did not provide details on this. Differences in brain development, particularly in frontal regions may impact executive functioning, which includes planning, self-control and adapting to change. Executive functioning differences are also commonly reported in individuals with ASD. Therefore, further research is needed to understand the underlying mechanisms and whether some suture types are more likely to be linked with ASD.

Although there is no clear evidence that children with single-suture craniosynostosis are more likely to have ASD than their peers, some may experience social difficulties or ASD-related traits. These findings suggest that monitoring social development and considering ASD screening within craniofacial clinics may help identify children who could benefit from further assessment and support.

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