Background: Approximately one-quarter of individuals with fragile X syndrome (FXS) meet diagnostic criteria for autism; however, it is unclear whether individuals with comorbid FXS and autism are simply more severely affected than their peers with only FXS or whether they have qualitatively different profiles of behavioural impairments. To address…

Background: There is a lack of empirical research investigating challenging behaviour in children with autism with severe speech impairments in naturalistic settings. The aim of the present study was to investigate challenging behaviour among Australian and Taiwanese children with autism who are non-verbal or have limited speech (i.e. less than…

Background: It is not known whether those with co-morbid fragile X syndrome (FXS) and autism represent a distinct subtype of FXS; whether the especially severe cognitive delays seen in studies of young children with co-morbid FXS and autism compared with those with only FXS continue into adolescence and young adulthood; and whether autism in those…