Investigating Autistic Spectrum Disorder related behaviours, including sensory difficulties, in girls with Fragile X Syndrome

Abstract

Thesis Abstract: There is very little research for females with Fragile X Syndrome (FXS) examining their ASDbehaviours, with most research focusing on males. This thesis examines the prevalence of ASD in FXS and the specific behavioural and psychological phenotype for girls with FXS.Literature Review:Whilst up to 60% of males with full-mutation Fragile X syndrome (FXS) meet criteria for autism spectrum disorder (ASD), the prevalence and nature of ASD in females with FXS remains unclear. A systematic literature search identified papers reporting ASD prevalence and/or symptomatology in females with full-mutation or pre-mutation FXS. Meta-analysis estimated pooled prevalence of ASD for the full mutation at 17% (95% CI 11 to 24%), and for the pre-mutation 3% (95% CI 0% to 17%), using a quality effects model. Whilst papers highlighted a number of social and repetitive difficulties, characteristic profiles of impairment are not clear. Possible associations of ASD traits with IQ and levels of fragile X mental retardation protein are suggested, but data are equivocal.Research Report:Whilst Fragile X Syndrome (FXS) is the most common inherited single-gene cause of intellectual disability and Autism Spectrum Disorder (ASD), research is dominated by male samples, and the understanding of ASD-related behaviour and other behavioural/psychological characteristics in females remains relatively unestablished.Parents/caregivers of girls with FXS were compared on ASD-related behaviours, including sensory difficulties, together with ability, mood, activity levels and challenging behaviour with those of boys with FXS and typically developing children. A number of behavioural/psychological difficulties are less pronounced in girls than boys with FXS, but they exceed those associated with typical development. This study also provides the first evidence of sensory processing difficulties in girls with FXS and suggests that they may relate to other elements of ASD-related behaviours and not to lower ability in girls with FXS.