Brief Report: Autism Symptoms in Infants with Fragile X Syndrome

Abstract

Fragile X syndrome (FXS) is the most common known genetic cause of autism spectrum disorder (ASD). Although 50–75 % of children with FXS meet ASD criteria, no studies have compared ASD symptoms in infants with FXS versus other high risk groups, such as siblings of children with ASD (ASIBs). Using the Autism Observation Scale for Infants, our findings indicate that 53 % of 12-month infants with FXS fall in the “at risk” category compared to 17 and 6 % for age-matched ASIBs and controls, respectively. Elevated atypical motor behaviors were associated with elevated risk for FXS. Cross-syndrome comparisons are essential to understanding the heterogeneity of ASD and identifying candidate markers that will facilitate differential diagnosis of ASD in genetic disorders such as FXS.

Behavioral Markers of Emergent Stranger Anxiety in Infants and Toddlers with Fragile X Syndrome

“…One interpretation could be that participants with emergent autistic symptoms experience less stranger fear, signaling blunted emotional responsiveness. However emergent autistic symptoms in FXS may also be associated with difficulty planning and coordinating motor behaviors, consistent with mounting evidence that motor coordination and planning may co-occur with or precede autistic symptomatology, both in FXS (Roberts, Tonnsen, McCary, Caravella, & Shinkareva, 2016) and non-FXS samples (Zwaigenbaum, Bryson, & Garon, 2013). Notably, base rates of autism-associated motor control abnormalities are also generally elevated in FXS, with up to 80% of infants with FXS scoring “atypical” on behavioral motor-related ratings compared to 12% of control infants and 14% of infants with family histories of ASD (Roberts, Tonnsen, et al, 2016).…”

“…Within FXS, patterns of behavioral inhibition have been established in older children and adults, although studies in infants and young children are sparse (see Tonnsen & Roberts, 2016, for review). During social challenge tasks, children with FXS exhibit higher rates of gaze aversion, task avoidance, behavioral distress, and abnormal vocalizations relative to their unaffected siblings (Hall, Lightbody, Huffman, Lazzeroni, & Reiss, 2009; Hessl, Glaser, Dyer-Friedman, & Reiss, 2006).…”

Infant Development in Fragile X Syndrome: Cross-Syndrome Comparisons

“…In our work, we found that motor items on the Autism Observation Schedule for Infants (AOSI; Bryson et al, 2008) discriminated ASD features in infants with FXS (Roberts et al, under review). Indeed, motor abnormalities have been described as a putative endophenotype for ASD potentially pointing to mechanistic factors as both motor and social-communication deficits have been indirectly associated with the same physiological systems (Esposito & Pasca, 2013).…”

Autism throughout genetics: Perusal of the implication of ion channels

“…X‐Fra syndrome is the second major cause of intellectual disability, which is caused by the expansion of CGG trinucleotide repeats in the FMR1 gene located on chromosome X and that encodes FMRP. This protein plays an essential role in synaptic plasticity by regulating mRNA trafficking in the brain (Devlin & Scherer, 2012; Roberts, Tonnsen, McCary, Caravella, & Shinkareva, 2016). …”