Most caregivers claim that children with fragile X syndrome (FXS) show signs of social avoidance, unresponsiveness or lethargy and irritability, confirming the utility of a set of subscales traditionally used to evaluate the behavior of individuals living with the disease to assess core behavioral symptoms of FXS in clinical trials.
The findings were described in a poster titled, “Content Validity of the ABC-CFXS and Subscales in Fragile X Syndrome,” presented during the 22nd Society for the Study of Behavioural Phenotypes (SSBP) Research Symposium, held Sept. 5–6 in Birmingham, England.
The Social Avoidance, Irritability, and Socially Unresponsive/Lethargic subscales of the Aberrant Behavior Checklist Community: FXS Specific (ABC-CFXS) is a 58-item rating scale that has been traditionally used to assess the severity of inappropriate behaviors displayed by children with fragile X in six categories: irritability, social withdrawal, stereotypic behavior, hyperactivity, inappropriate speech, and social avoidance.
However, the content validity of the ABC-CFXS scale to assess the main symptoms of fragile X in children had never been systematically evaluated from the perspective of caregivers.
The study, sponsored by Zynerba Pharmaceuticals, used carers’ perspectives to assess how appropriate the ABC-CFXS scale would be to evaluate behavioral abnormalities in children with fragile X and to measure primary and/or secondary endpoints in clinical trials evaluating possible therapeutic interventions.
The study involved 10 caregivers of children with fragile X, who were asked to use an online journal for five consecutive days to document all types of behaviors displayed by the children for whom they were caring. After five days of journaling, all caregivers underwent a semi-structured, in-depth interview so that researchers could gather their feedback and experiences.
Data showed that nine of the 10 caregivers participating in the study reported at least one behavior that fell within the categories of social avoidance, social unresponsiveness or lethargy, and irritability, all assessed in the ABC-CFXS scale.
Moreover, most behaviors described by caregivers strongly matched the individual items evaluated by the ABC-CFXS scale. For instance, 70% of the caregivers reported children often sought to be alone, preferred to be alone (40%), or to perform activities alone (20%), all of which fall into the category of social avoidance.
The categories of irritability and social unresponsiveness or lethargy also matched with many behaviors described by carers, including being aggressive to others (60%), showing signs of irritability (50%), having temper tantrums/outbursts (50%), screaming or yelling (40%), having lack of interaction (60%), and lack of attention (50%).
“Fragile X syndrome is a complex diagnosis for a child and his/her family, marked by myriad specific behavioral and emotional symptoms often manifesting as anxiety and social-avoidant behaviors,” Terri Browning Sebree, Zynerba’s president and study author, said in a press release. “Through studies like this one, we are able to not only elucidate the most common core behaviors of FXS, but also further validate the appropriateness of the ABC-CFXS as an effective tool for use in clinical studies as a means to measure improvements in these core and common FXS behaviors.”
Zynerba is now planning to use the ABC-CFXS scale to evaluate potential improvements in the behavior of children with fragile X participating in the company’s CONNECT-FX trial (NCT03614663) a 14-week pivotal study assessing the efficacy of Zygel (ZYN002), a cannabidiol gel formulation that is thought to ease anxiety and other behavioral symptoms in children and adolescents with fragile X.