Fragile X syndrome (FXS) is the most common genetically-inherited neurodevelopmental disorder, characterised by intellectual impairment, difficulties in social interaction and communication, weaknesses in attention and behaviour and autistic traits. A mutation in the FMR1 gene on the X chromosome leads to an expansion of the CGG trinucleotide from normal levels (<50) to over 200 repeats, causing inactivation of the gene and the complete loss of the protein that is produced by the FMR1 gene.
As this protein (FMRP) is crucial in plasticity of synapses in the brain (i.e. formation of connections and reformation during development), individuals with FXS have a range of neurologically-based weaknesses in cognitive, behavioural and motor domains. These weaknesses affect males and females differently however, as the single X chromosome expressed in males generally leads to symptomology with greater severity, as the extra X chromosome expressed in women is often unaffected. As a result, it is important to look at the different strengths and weaknesses in ability between genders, in order to implement efficacious interventions for both males and females.
This project looks to integrate a number of disparate areas of functioning in FXS to determine if interactions may be present between different domains in males and females, in order to increase our understanding of the strengths and weaknesses associated with FXS.
The first aspect of this project will focus on motor abilities and dual task performance in individuals with FXS, domains that are often overlooked in the literature. Using measures of gait and stepping ability, we aim to determine the pattern of motor performance in males with FXS and compare these to individuals with other neurodevelopmental disorders, such as Williams syndrome and Down syndrome, as well as comparisons to typical development. Furthermore, the addition of dual motor and cognitive-motor tasks to be performed simultaneously on these paradigms will provide crucial data on how the attentional control weaknesses often observed in FXS relate across-domains into motor performance.
The second aspect of this project will link Theory of Mind and social cognition in FXS with their motor abilities, using both an eye-tracking system to monitor the motor movements involved in social scene perception and the gait and stepping paradigms mentioned above. It is hoped that the difficulties observed in FXS in regards to emotional processing and social anxiety may show some relation to motor control, providing a further example of cross-domain interaction in the FXS brain which may allow researchers to determine underlying neural pathways that are significantly affected by this condition.
Professor Kim Cornish
Doctor Darren Hocking
Ms Hannah Kirk