Children with fragile X syndrome exhibit abnormal gesture use (a form of non-verbal communication) early in development, partially accounting for autism spectrum disorder (ASD) symptom severity, according to a recent study.
Individuals with fragile X syndrome experience several social and developmental difficulties; problems with social communication are a particularly limiting aspect of the disease.
During typical development, nonverbal behaviors, such as gestures, occur early in infancy preceding verbal communication. They become the building blocks for more complex social communication skills (words and language).
Increasing evidence suggests that children with fragile X — the most common known single gene cause of ASD — exhibit abnormal gesture use early in development, which is a hallmark symptom of young children with ASD.
However, few studies have investigated the nature of abnormal gesture use in very young fragile X children and the impact of ASD features on this behavior.
Researchers compared gesture use in 86 male infants: 39 fragile X children; 27 infant siblings of children with ASD (high-risk siblings), and; 20 low-risk infants. They were assessed at 9, 12 and 24 months of age.
Individuals were recruited through an ongoing longitudinal study at the University of South Carolina aimed at detecting the emergence of ASD in infants and young children with fragile X.
At two years of age, infants with fragile X used, on average, four less gestures than high-risk siblings and about six fewer gestures than low-risk infants.
ASD symptom severity between groups, assessed with the Autism Diagnostic Observation Schedule, Toddler Module, had no association with differences in gesture use or development between fragile X and high-risk siblings, or between fragile X and low-risk infants.
However, when the impact of ASD symptom severity in both fragile X and high-risk siblings was assessed individually, researchers observed that higher ASD symptom severity was associated with fewer use of gestures in both groups.
No association was detected for the degree of symptom severity and the rate at which infants acquired gestures over time.
“These findings offer novel evidence that early gesture use in FXS may reflect broader features of the FXS phenotype, rather than specifically predicting later social-communicative deficits characteristic of comorbid ASD,” researchers wrote.
“…targeting an increase in number of gestures used in FXS early in development may promote a trajectory more closely matched with the one observed in typical development,” they concluded.